Serbia defender Ivanovic was one of five players who took a limited part in training ahead of the tie but scored a vital away goal at Parc des Princes, where goalkeeper Courtois excelled after returning at the expense of Petr Cech.
"If you go to chances created and goalkeeper performances, you have to be honest and say they have more than us," Mourinho said.
"If someone was closer to winning the game it was Paris, not Chelsea."
Courtois made a number of fine saves, particularly to deny PSG scorer Edinson Cavani in the first half and Zlatan Ibrahimovic in stoppage time.
"If football was nine outfield players plus two goalkeepers we would give no chance to anyone," Mourinho added.
"We would be absolutely phenomenal, because they are both phenomenal."
Ibrahimovic said: "The goalkeeper did a very good job, don't take that away from him.
"He's a world-class goalkeeper and he showed it
Let's see how we do in the second game to get the ball past him."
Chelsea lost 3-1 at Parc des Princes last season, but advanced to the semi-finals at PSG's expense on away goals.
PSG boss Laurent Blanc rued the concession of an away goal, but believes his side are capable of upsetting Chelsea in London.
"The result is not in our favour," he said.
"I'm satisfied by my team, by my players
It was almost perfect
Unfortunately we conceded a goal.
"In the last two games we've had in the knockout phase of the Champions League, the away goal cost us qualification
We have to remember that.
"Chelsea have a slight advantage playing at home in the second leg, and we know they're strong on the counter-attack so we can't just go gung-ho.
"But we have very good attacking players
We know we can score against anyone and from anywhere."
Illness and injury hampered Chelsea's preparations.
"(Eden) Hazard, Willian, Oscar, (Cesc) Fabregas, Ivanovic, they didn't train," Mourinho said.
"They did some individual training just to try to keep rolling and moving
(On Monday) they trained because you (the media) were there.
"Fabregas had three days in bed, came to play without training
Injured guys (played) without training
They gave everything."
Ivanovic scored the decisive goal in the 2013 Europa League final and netted against Liverpool last month as Chelsea advanced to the March 1 Capital One Cup final.
"Iva has more this feeling in big occasions," Mourinho added
" It looks like he chooses the moment."
Mourinho played down Chelsea's favourites' tag.
"The advantage is minimal," he added
" It's not a victory, 3-0 or 4-0 that ends the story
They are a fantastic team, fantastic players
We did okay."
Source : PA
Source: PA