Wing Shane Williams scored five of the Lions' 17 tries and, although Manawatu were clearly inferior opponents, it was still a job well done.
"It was the biggest statement possible from this team," said McGeechan. "They played as a team, rather than the individuals they were against Southland last week.
"I think it was very important to have a game like that. I don't care what the opposition would have been - that team was ready."
McGeechan conceded the game was "miles away from a Test match," but added: "Just to see the smiles afterwards on the faces of the non-playing group was a good buzz.
"It was important we showed that we could play rugby, and it lifts a dark cloud. It was a big statement of the attitude of the players - they kept playing rugby."
The Lions were also able to report a largely injury-free outing, although hooker Gordon Bulloch and his replacement Andy Titterrell did pick up knocks, while lock Brent Cockbain acquitted himself well when he appeared off the bench.
Wales lock Cockbain only arrived in Palmerston North by helicopter a few hours before kick-off, having flown from Sydney to Wellington after answering head coach Sir Clive Woodward's call when Danny Grewcock landed a two-month ban for biting All Blacks hooker Keven Mealamu.
"We wanted to get the tour back on route," said skipper Bulloch. "Against Southland, we played as individuals, whereas this was a team performance."
And fly-half Charlie Hodgson added: "Everyone is delighted. All the boys (Lions squad) came around and shook everyone's hand.
"Last weekend was disappointing, and it was important to get things back on track."