Fernando Torres, a £50million signing from Liverpool in January 2011, was not selected to start the quarter-final first leg at Parc des Princes, with Andre Schurrle preferred as a 'false nine'.
And Mourinho was left to glance enviously at a PSG side featuring Zlatan Ibrahimovic, Edinson Cavani and Ezequiel Lavezzi, who scored the opening goal in the hosts' 3-1 quarter-final first-leg win.
"I'm not happy with my strikers' performances, so I have to try things," Mourinho said.
"With Andre at least I know we have one more player to have the ball, we have one more player to associate with the other players.
"Football is also about scoring goals. That is for strikers, for real strikers. I had to try."
Mourinho was scathing in analysing Chelsea's performance, lamenting individual mistakes and a "joke" third goal conceded by the 2012 European Cup winners.
Eden Hazard's penalty had given the Blues a potentially vital away goal, but Javier Pastore's brilliant stoppage-time solo effort, added to Lavezzi's strike and a David Luiz own goal, saw PSG take a two-goal advantage into next week's second leg at Stamford Bridge.
Mourinho said: "The third goal was a joke. It's not a goal. It's a joke.
"We enjoyed the third goal with Pastore. The third goal was Pastore and us.
"We made individual mistakes in areas where for the whole season the guys perform and we have no problems.
"They have the right to make their mistakes, because we have other players that make mistakes the whole season. We paid the price.
"The ball goes to Lavezzi in the first goal, control, half-volley, boom. Top player, top striker. It's like this at this level, one chance, one goal.
"It's difficult for us to score goals. It's difficult for us to score goals, especially when the games are tight.
"It's difficult for us to transform the half-chances into chances and when you make defensive mistakes you are in trouble. That's, for me, simple."
Chelsea, beaten by Crystal Palace last Saturday, have now lost three of their last five games after just one defeat in the previous 17.
But Mourinho maintains the Blues can advance to the semi-finals for a seventh time in 11 years.
"We have nothing to lose now," Mourinho said.
"When you are losing 3-1 there is no approach. We have to try to win 2-0, 3-1, 4-1.
"We have to play thinking that it's possible. And, to be fair, I don't think Paris think that it's done. I think they feel they are in a good position, but I think they know that it's not over."
PSG boss Laurent Blanc believes the third goal will give the return a different complexion.
"Sometimes it's difficult to concede in the last minute," Blanc said.
"It would've been different at 2-1, with an away goal.
"We're aware that 3-1, it will still be a difficult game over there.
"For the second leg Chelsea will have to attack and we might have some opportunities to play on the counter attack.
"It will be an exciting game but quite a difficult one over there."
PSG may travel to London without Ibrahimovic after the striker suffered a hamstring injury midway through the second half.
Blanc said: "He has a muscular problem. He'll probably need to do a few more exams tomorrow.
"We need him, but we had to deal with this situation during the game."
Blanc was pleased with the opening 15 minutes and thrilled with the second-half display.
"This is very encouraging for us. At half-time we were wondering if we were the same level as Chelsea," Blanc said.
"We had a very good discussion. We had played 15 very good minutes then nothing.
"The second half was really excellent and we made it really difficult for Chelsea and scored two goals."