A 3-1 first-leg loss at the Parc des Princes leaves Chelsea clinging to the hope that they can replicate their comeback against Napoli en route to winning the tournament against the odds in 2012.
"We need a massive performance in the second leg now," defender Gary Cahill told Chelsea TV.
"We need the performance that we had against Napoli the year we won it."
Andre Schurrle, deployed as a 'false nine' in Paris, added on uefa.com: "It was a bad result for us - we'd hoped for better.
"It's still possible, we can still do it, but we need to create more chances and then who knows? Maybe we'll pull it off."
Against a PSG side led by Zlatan Ibrahimovic - now doubtful for the second leg with a hamstring injury - and featuring Edinson Cavani and Ezequiel Lavezzi, both members of the Napoli side beaten in the last-16 two years ago, Mourinho chose to demonstrate his lack of firepower.
The last time a Chelsea manager fielded a team without a recognised striker and an away defeat left the Blues on the brink of elimination, European Cup-winning boss Roberto Di Matteo was sacked following a 3-0 loss at Juventus.
The future of Mourinho, who signed a four-year contract on his return last June, is not in doubt, but the strength of his influence at Stamford Bridge will be examined in the coming months, with owner Roman Abramovich likely to be asked to dig deep to recruit the striker his manager wants.
In the era of Financial Fair Play, Mourinho may have to sell and remould his squad to finance any deal for the type of "killer" striker he believes Chelsea need.
What it means for Chelsea's current trio of strikers - and Romelu Lukaku, who is on loan at Everton - is uncertain, but Mourinho did not hide his disdain after the Paris performance.
Samuel Eto'o, out with a hamstring injury for the last two games, may not be the target of his dissatisfaction, but Demba Ba has been used sparingly and Fernando Torres was overlooked in favour Schurrle leading the line.
Torres, signed for £50million from Liverpool in January 2011, can regard his Chelsea career as over, according to former Blues captain and assistant boss Ray Wilkins.
Wilkins told talkSPORT: "Torres has no future at Chelsea. I think he has seen his time out there. He needs to try and make something happen."
Whether or not Eto'o is fit, available and trusted for next Tuesday's second leg is uncertain as Chelsea - following the Champions League win in 2012 and Europa League triumph last term - aim to maintain their record of being the last English team standing in Europe in recent seasons.
Eden Hazard's penalty, cancelling out Lavezzi's opener, had given Chelsea a vital away goal, but a David Luiz own goal gave PSG a slender advantage and Javier Pastore's stoppage-time third could prove decisive as the Blues suffered a third successive away loss.
Cahill added: "At 2-1 would have been different than 3-1. We're disappointed.
"We need a massive performance. We've got the characters and we have got the performance at home.
"Of course it's going to be tough and the blow was the goal at the end which was very soft and unlike us."
Ramires, who will miss the second leg through suspension, said on uefa.com: "Nothing is lost yet, we have to score two goals and we're averaging a good amount of goals at home, so we have what it takes to reach the next stage.
"We played against Napoli and we won, and now we will have 90 more minutes to play against Paris.
"It's no use saying who is stronger; we have to show on the pitch that we deserve to win."
Lavezzi is not prepared to contemplate another European exit after taking a handsome lead to Stamford Bridge.
He said on uefa.com: "The goal at the end was very important, and it was important for the team to win a match like that.
"We'll go to London for the return leg with a little more peace of mind.
"I'm not worried about Chelsea pulling off a repeat of their comeback against Napoli because this is a completely different team and we hope to go through."