Sir Clive Woodward's side were convincingly beaten 21-3 in Christchurch and also lost skipper Brian O'Driscoll for the rest of their tour to a dislocated shoulder.
However, Marshall warned reaching the same level in the second Test would be tough for his team-mates.
"Next week is going to be a completely different kettle of fish," he said.
"We took a bit out of the game but the Lions will have taken a hell of a lot out of it as well.
"They would have looked at the set-piece, our lineout and our scrum, which they hadn't come up against before and they will be a lot better for it."
Australia captain George Gregan warned Marshall to be prepared for a sea of red at the Jade Stadium on Saturday.
With vast swathes of Lions supporters in full voice in the stands you could have been forgiven for thinking that the British and Irish team were playing in front of a home crowd rather than in New Zealand.
Four years ago the Wallabies were stunned by the vast number of Lions fans and their vocal support at the Test in Brisbane, but the noise and the electric atmosphere on Saturday came as no shock to Marshall.
Marshall added: "George Gregan actually sent me a text earlier in the week that said don't be surprised to learn that half the crowd are probably going to be Lions supporters. He said they got a real shock in Brisbane four years ago."
Marshall, a stalwart of the Canterbury and Crusaders teams who play at Jade Stadium, described the atmosphere for his final match at the ground as the best he had ever experienced at Test level as the veteran scrum-half heads to Leeds after the three-Test series.
He added: "It was absolutely fantastic. It's the first time I've heard the New Zealand crowd sing for a while; they really got stuck into it. Atmosphere-wise it was just the best."
New Zealand's pack dominated throughout the victory, especially in the lineout, and Marshall was quick to pay credit to his forwards.
"They laid a fantastic platform," he said.
"It could have been a difficult night for me but it wasn't because of what was done up front and I'm really thrilled that they played the way they did because it made my job a hell of a lot easier than it could have been."
One of the reasons for New Zealand's improvement in the set-piece had been down to learning from northern hemisphere teams Marshall revealed.
He added: "More than anything we've tried to learn a little bit off the northern hemisphere sides and we've really targeted, particularly from the middle of last year and through this year, the set-piece. It's such an important part of the game now.
"Now it's just a mental thing. It's not 'oh no we're never going to be able to compete; we're never going to have the same sort of advantage as the bigger sides do'.
"It's all myth now because we've shown that we can do it. It's just a matter of getting that consistency."