Cesc Fabregas scored an 88th-minute winner at Loftus Road to restore Chelsea's advantage over second-placed Arsenal and maintain the side's march towards the title.
The Spaniard's strike was Chelsea's only shot on target during a disappointing West London derby, which QPR could have won had Thibaut Courtois not denied Matt Phillips' close-range effort in the second half.
"Were we fortunate? Yes
It was a typical game for 0-0," Mourinho said.
"We controlled them very well and kept them far from the box because in the box (Bobby) Zamora and (Charlie) Austin are killers.
"They closed us down very well, they were very well-organised defensively and gave us a difficult match.
"I am obviously very happy with my team because we kept good emotional control, we never lost balance or were under pressure.
"We were always very stable and then we scored in the crucial moment of the game - I feel sorry for them because they fought hard to get a point."
The victory comes as another blow to the fading hopes of the chasing pack, with Arsenal, Manchester United and Manchester City all trying to close the gap on the league leaders.
Chelsea have been joint top or top of the table since the opening day of the season and are on course to break Manchester United's 1993/94 record of 262 consecutive days at the summit.
"I don't know if it hurts them (our rivals) or not, what I know is it's not normal to be top of the league since day one," Mourinho said.
"A team who arrives in August and is top of the league every day until April - that is the team that deserves the credit.
"We have had a good run since day one so nobody should be disappointed because we have been on a good run since August
Now we need 11 more points (to win the title)."
Courtois' strong performance will be a welcome boost for the Chelsea keeper, who has endured a difficult few weeks.
The Belgian's skewed kick led to a goal against Hull last month and Charlie Adam's wonder-strike saw him beaten from 66 yards against Stoke last weekend.
"He helped us win the match," Mourinho said.
"I thought Courtois did very well, he was there for us.
"I told him at the start of the week after Hull and after Charlie Adam, we need him to give us a couple of points with a couple of saves and he did it."
The result leaves QPR two points adrift of safety, having played one game more than Burnley, Sunderland and Hull, and two more than Leicester.
Rangers boss Chris Ramsey defended his goalkeeper Rob Green, whose skewed clearance gifted Chelsea possession in the build-up to the goal, and lamented his players' poor defending.
"I am very disappointed, disappointed in the manner we let the goal in," Ramsey said.
"I'm not blaming Rob for the goal, it wasn't one of his best kicks but we had a long time to defend it properly and we didn't.
"When the ball goes out wide and we've got about eight players behind the ball you can't blame him, it's just a bad clearance.
"The way we let the goal in at the end was one we could have defended miles better than we did
All that running everyone does has now gone to waste.
"The fans were fantastic and the players did give them something to hope for, for most of the game.
"The reason I'm sitting here sick is we could have given the fans a big boost by getting a point here against a top team."
Source : PA
Source: PA