The Blues, managed by Liam Rosenior, travel to France for the first leg of the round of 16.
Gusto expects a "completely different" encounter compared to their meeting in the final of the Club World Cup, where Chelsea dominated and lifted the trophy.
In that match, PSG were widely regarded as "very poor" and "very easy to beat," while former Chelsea manager Enzo Maresca and his squad earned praise for their commanding display.
Despite that comfortable past result, Gusto is bracing for a far more competitive scenario. He suggested the match could go either way.
"I think tomorrow will be completely different [to the Club World Cup final] as a contest," said Gusto via X.
"This is the Champions League, so it's very different [type of game] and it's a completely different competition."
Premier League rivals Liverpool experienced the challenges of playing away in the Champions League on Tuesday night as they lost 1-0 at Galatasaray.
Kai Havertz will return to familiar surroundings on Wednesday when Arsenal face Bayer Leverkusen in the first leg of their UEFA Champions League last-16 tie, a match that carries renewed motivation for the German forward after an injury-plagued year.
Atalanta were humbled 6-1 by Bayern Munich in the first leg tie of the UEFA Champions League Round of 16 at the Gewiss Stadium in Bergamo on Tuesday.
Diego Simeone's Atletico Madrid thrashed Tottenham Hotspur 5-2 in the first leg of their Champions League last 16 encounter on Tuesday evening, to all but end the tie as a contest.
A dramatic stoppage-time penalty from Lamine Yamal rescued a 1-1 draw for Barcelona against Newcastle in the first leg of their UEFA Champions League Round of 16 tie.
