Victory for New Zealand in next Saturday's third encounter at Eden Park would complete a series 'blackwash' and confirm the Lions' worst set of Test results since they lost all four games against the All Blacks 22 years ago.
A week after their Christchurch loss, the Lions played with renewed passion and purpose, but hopes of taking a one-sided series into a decider were smashed beyond repair with a 48-18 defeat.
All Blacks fly-half Dan Carter was their nemesis, amassing a New Zealand record 33 points against the Lions, although together with centre Aaron Mauger, he now misses the Auckland finale through injury.
It was the highest number of points ever conceded in a Test match by any Lions team, stretching back 114 years, and their second-heaviest defeat following a 38-6 All Blacks thumping in 1983.
Thomas is adamant however that his players' thoughts are not on the flight home, declaring: "We are going to approach next Saturday as if it was a Test match to win the series.
"At the end of the day, we can't just go out there because the series has been lost, put on a Lions jersey and just go through the 80 minutes because the series is over.
"There is so much history and so much behind the Lions jersey. This is the pinnacle of our careers, and for us to just go out and accept another loss because we can't win the series would be a disgrace to the jersey.
"We went out there to try our best. I don't care what reports will be written, or what people will read into the scoreline, as far as I am concerned, from one to 22 the guys gave everything they had.
"On the day, we weren't good enough.
"New Zealand are a complete team at the moment. They can mix it with the toughest teams, they can run it with the fastest teams. You can't relax against these guys, they can attack from anywhere.
"The scoreboard, to me, is totally irrelevant. Last week in Christchurch it was an 18-point difference, but the game was terrible from our perspective, and this time we went out, enjoyed it and got great passion and pride out of our display."
Ultimately it all ended in despair for the Lions, who made a stunning start and were ahead inside two minutes when Thomas left a bewildered All Blacks defence leaden-footed and scored through an arcing solo run.
Jonny Wilkinson converted, and then hit the post with a penalty attempt, but once the Carter-inspired All Blacks got going, they proved unstoppable.
The Lions play Auckland on Tuesday followed by the All Blacks again, and forwards Steve Thompson and Lewis Moody believe that they can secure a morale-boosting win.
"International rugby is about one or two per cent, that's all it is. There is not a massive difference between the teams," said Thompson.
"But sometimes, you have got to take your hat off and say fair play to them. A couple of times, we got scores and then lost the ball when we could have turned the pressure back on them, and I thought that was the difference."
Leicester flanker Moody added: "We wanted to go out and play rugby, and we will want to do it next weekend. These guys are not invincible, as we proved in the first half, it's just a matter of maintaining focus for the full 80 minutes.
"Carter undoubtedly had a great game, but this team is beatable, which makes it even more frustrating that we let it slip away in those first 10 minutes of the second half."