Manchester United's 2-0 victory over West Brom at Old Trafford means their city rivals will go into next weekend off the top of the table for the first time since October 15th.
But Mancini feels a second 1-0 defeat in four days, following Thursday evening's Europa League reverse at Sporting Lisbon, does little to alter the overall title picture, and said: "It's been difficult the last four days for me, but football is this - sometimes you can lose."
He added: "I don't think that we deserved to lose this game. I should say that Swansea played very well in the first 30 minutes. They played very good football. But in the second half we had control of the game. We missed three or four chances on the counter-attack and we conceded a stupid goal.
"Now it's important that we are very confident together because it changes nothing. It is better to stay on the top and now we are behind, but this doesn't change our targets."
The manner of Swansea's performance delighted manager Brandan Rodgers.
"Sometimes you get results where you take on the big guns of European football when you win the game 1-0 and you're maybe hanging on, but we were the better side," he said.
"In the second half when we scored, I think that was when we showed our maturity tactically. We dropped on our lines and blocked spaces. It was very, very difficult for them to get through us
"Over the course of the game, some of the passing and moving and ball retention against top players was phenomenal.
"We got one goal, we missed a penalty, we could have had one or two more and I think the players deserve every credit that they get for their technical ability in the game, as well as that mentality to want to take on a top team."
Source: PA
Source: PA