Despite plenty of public and private debate beforehand, there was no question as to who was the better team when the sides went head to head in the first of three internationals.
And while defeat ultimately paved the way for one of the most impressive comebacks in Lions history, the four-try hammering was a major disappointment at the time.
AUSTRALIA 30 BRITISH & IRISH LIONS 12
Scorers: Australia: Tries - Martin, Walker, Maquire, Gourley; Cons - Lynagh 4; Pens - Lynagh; Drop goal - Lynagh Lions: Pens - G Hastings 2, Chalmers; Drop goal - Chalmers
SETTING THE SCENE
The 1989 Lions created history even before they played their very first match Down Under. As the first tourists in 90 years to travel to Australia as a solitary destination, this particular pride of Lions and this particular tour paved the way for the 12-year-cycle of the three giant southern hemisphere nations that we have now become accustomed to.
And things started so brightly for Britain and Ireland's elite in the first tour of any sorts for some six years. Having missed out on the chance to travel to South Africa due to the political and sporting boycott, the Lions hadn't been away - bar a single celebratory fixture in Paris - since the underwhelming series in New Zealand in 1983.
With many of the players involved having had to wait longer than normal to pull on the famous red shirt, the class of '89 clearly had a point to prove. And they proved that point in style early on, winning all six matches in the lead up to the opening Test.
Finlay Calder and co arrived in Sydney in high spirits after a strong start to the tour
While it was true to state that much had been made of the perceived lack of strength in depth in Australian rugby at the time, the Lions did what they needed to do and more.
Comfortable wins over Western Australia, Queensland B and New South Wales B, sandwiched with more challenging but ultimately victorious encounters with Australia B, Queensland and New South Wales, appeared to have given the Lions the perfect preparations for the start of the Test series.
Injuries robbed the Lions of players of the calibre of Chris Oti, John Devereux and soon-to-be man of the tour Mike Teague for the series opener but the tourists still arrived in Sydney full of confidence. England may have been beaten twice by Wallabies and by New South Wales when they toured Australia the previous year but six wins on the spin, combined with the stiff competition for places being provided by the 'dirt trackers', saw McGeechan's men start their Test adventure in high spirits.
Unfortunately for the Lions, those spirits were dampened pretty quickly and comprehensively in the first Test, making it even more remarkable that a fortnight later they would become the first official Lions side to turn a 1-0 deficit into a 2-1 success.
Apart from including just a single Irishman in the starting line up, the team for the first Test was pretty cosmopolitan. Wales and Scotland contributed five players apiece and England provided four for a much-talked about opening rubber.
Gavin Hastings, Rory Underwood and Ieuan Evans started the first of what would be six successive Lions Tests together and the trio were among 14 starters taking part in their first-ever Lions international.
Only Wales lock Robert Norster had tasted Test action with the Lions, with the Cardiff veteran having played in the first two internationals in '83. Norster missed the third and fourth Tests in New Zealand six years prior to this tour, however, meaning McGeechan was naming an entirely different side to the one that had last featured in an international for the Lions.
In midfield, Brendan Mullin and Mike Hall won a tight battle for the centre spots ahead of Scott Hastings and Jerry Guscott, with Devereux unavailable through injury.
Ireland's Brendan Mullin started in the centre alongside Mike Hall
Craig Chalmers was handed the No10 shirt after Ireland's Paul Dean saw his tour ended in the opening game in Perth three weeks earlier, while Robert Jones, who was to have such a big impact on the outcome of the series, was selected at scrum-half.
In the forwards, David Sole started at loosehead prop just a few months before leading Scotland to Grand Slam glory, with England's Brian Moore and Welshman Dai Young named alongside him in the front row. All three men would be ever-present throughout the '89 series, but only Moore would feature for the Lions in New Zealand four years later. For Young, who missed the 1993 adventure due to a spell in rugby league, this was the start of a remarkable Lions career that spanned three decades and lasted until the first tour of the 21st century.
England hooker Brian Moore was an ever present in the three-match Test series
Nortser was joined in the second row by England's Paul Ackford, with the pair among just four players 30 years or over in the Test team. Tour captain Finlay Calder and Scotland team-mate Derek White - the other two 30 somethings - were named on the flanks, with Dean Richards at No8.
As for the Australians, six players from the final game of the famous Grand Slam tour of Britain and Ireland in 1984 featured again in the starting line up. Legendary figures David Campese, Michael Lynagh and Nick Farr-Jones made up half that number, with forwards Tom Lawton, Steve Cutler and Steve Tuynman also having tasted glory on Home Union soil.
Campese, Lynagh and Farr-Jones were the only men who would remain Wallaby starters for the 1991 World Cup Final, however, as the Lions' success later in the series forced an Australian rethink.
Australia: Greig Martin (Queensland); Acura Niuquila, Lloyd Walker (both New South Wales), Dominic Maguire (Queensland), David Campese (New South Wales); Michael Lynagh (Queensland), Nick Farr-Jones (New South Wales); Cameron Lillicrap, Thomas Lawton, Dan Crowley, William Campbell (all Queensland), Stephen Cutler (New South Wales), Jeffrey Miller (Queensland), Scott Gourley, Stephen Tuynman (both New South Wales)
Replacements used: Mark Hartill for Lillicrap, Mark McBain for Lawton
British & Irish Lions: Gavin Hastings (London Scottish/Scotland); Ieuan Evans (Llanelli/Wales), Mike Hall (Bridgend/Wales), Brendan Mullin (London Irish/Ireland), Rory Underwood (Leicester/England); Craig Chalmers (Melrose/Scotland), Robert Jones (Swansea/Wales); David Sole (Edinburgh Academicals/Scotland), Brian Moore (Harlequins/England), Dai Young (Cardiff/Wales), Paul Ackford (Harlequins/England), Robert Norster (Cardiff/Wales), Derek White (London Irish/Scotland), Finlay Calder (Stewart's Melville FP/Scotland), Dean Richards (Leicester/England)
Referee: K Lawrence (New Zealand)
The match itself was far more one-sided than anyone had anticipated. Whereas the pre-tour talk had been about whether Australia had the means to host a full Lions tour, the post-match discussions would centre on whether the Lions could bounce back from a substantial beating. For the Australian press the answer was a resounding 'no'.
The logic behind that assessment was pretty sound. The Lions were second best by a country mile at the Sydney Football Stadium.
The flyers failed to fire, with youngster Chalmers unable to get the best out of an initially exciting-looking back division. Few chances were created out wide, with Underwood, Evans, Hall and Mullins relying on scraps in comparison to the feast that was being experienced by opposite numbers Acura Niuquila, Campese, Lloyd Walker and Dominic Maguire.
Scotland's Craig Chalmers couldn't get his backline going in the opening Test
But it wasn't out wide where the match was lost: it was upfront, at rucks and mauls and scrums and lineouts, where the Lions' hopes were dashed.
The tourists had been expected to match the Wallabies for aggression and technical prowess but they fell short on both fronts.
Australia somehow seemed hungrier as they dominated the setpiece and were invariably first to the breakdown. And while Chalmers and Jones were rarely given front foot ball, Lynagh and Farr-Jones enjoyed an armchair ride as they ran the show for the Wallabies.
The golden boys of Australian rugby gave the Lions backs a rough ride as they demonstrated the kind of form that would seem them guide their country to World Cup success two years later. Lynagh's goal kicking was particularly impressive, with the fly-half converting each Wallaby try and kicking a penalty and a drop goal.
If the Lions had just been beaten by Lynagh's boot, the loss may have been easier to take. But it wasn't the case. While the scoreboard told of an 18-point defeat, the small print also showed that the Lions had been stuffed by four tries to nil. In today's age the Wallabies would have won with a bonus-point and at a canter.
Three of those tries were scored by outside backs, with full back Greig Martin and centres Walker and Maguire all crossing the Lions' line. The other score was claimed by back row Scott Gourlay, but in truth the damage was done by those even closer to the coalface.
Full back Gavin Hastings kicked two penalties but it wasn't nearly enough
WHAT THEY SAID
Clive Rowlands (Lions manager)
"Was I simply a one-eyed Welshman who, even in defeat, believed we were always better? Perhaps we had been over confident, but we certainly learned from the experience."
Finlay Calder (Lions captain)
"After the game, the press were calling for heads to roll, my own included. I called a management meeting and offered to stand down for the second Test. 'If you go, I must go also,' was all Clive (Rowlands) said. The matter was closed."
The Lions in Sydney:
The Lions have played 41 games in Sydney at an average of 3.5 on each tour. One of the world's most-talked about cities has featured in every single one of the Lions' 12 tours to Australia and hosted an incredible 20 matches across the first three of those adventures.
A total of 12 of the 41 fixtures have been Tests, with the Lions triumphing on eight occasions for a 66 per cent win rate.
It's the Wallabies who have enjoyed the first and the last laugh, though, thanks to victory in the first-ever Test in Sydney in 1899 and the most-recent encounter in 2001.
P 41 W 31 D 2 L 8
1888: New South Wales 2 Lions 18
New South Wales 6 Lions 18
Sydney Juniors 0 Lions 11
New South Wales 2 Lions 16
Sydney Grammar School 2 Lions 2
University of Sydney 4 Lions 8
1899: New South Wales 3 Lions 4
Metropolitan 5 Lions 8
Australia 13 Lions 3
New South Wales 5 Lions 11
Metropolitan 8 Lions 5
Australia 10 Lions 11
Australia 0 Lions 13
Combined Public Schools 3 Lions 21
1904: New South Wales 0 Lions 27
New South Wales 6 Lions 29
Metropolitan 6 Lions 19
Australia 0 Lions 17
Australia 0 Lions 16
New South Wales 0 Lions 5
1908: New South Wales 0 Lions 3
New South Wales 0 Lions 8
Metropolitan 13 Lions 16
New South Wales 6 Lions 3
1930: New South Wales 10 Lions 29
Australia 6 Lions 5
New South Wales 28 Lions 3
1950: New South Wales 6 Lions 22
Australia 3 Lions 24
Metropolitan 17 Lions 26
1959: New South Wales 18 Lions 14
Australia 3 Lions 24
1966: New South Wales 6 Lions 6
Australia 8 Lions 11
1971: New South Wales 12 Lions 14
1989: New South Wales 21 Lions 23
Australia 30 Lions 12
Australia 18 Lions 19
2001: New South Wales Waratahs 24 Lions 41
Australia 29 Lions 23
2013: New South Wales Waratahs 17 Lions 47