Manchester City boss Roberto Mancini has taken responsibility for the club's exit from the Europa League, saying his players were too complacent in the first half which cost them a place in the quarter-finals.
City went into the second leg at Eastlands a goal behind, and by half-time that was three as Sporting Lisbon took advantage of a poor foul by Mario Balotelli and slack defending.
A second-half onslaught came up short as City won 3-2 but went out on the away goals rule.
Mancini said: "In the first half we didn't play, but I am the manager and it's not the players' fault, but mine - I probably made a mistake. The players did everything, and fought on the pitch. When a manager doesn't prepare well for the game, this happens.
"When I lose a game I think about why I lost and think about where I made mistakes. I understand we have big players but in football every game is difficult, and in the Europa League and Champions League it is more difficult, because every team plays to win.
"Sometimes we make mistakes, but the manager is the person who always prepares the game, and I probably made some mistakes for these two games.
"I am proud for the second half because we had a fantastic 45 minutes, but I am very sorry for the players and our supporters because they were fantastic in that second half.
"But I am disappointed in myself, not the players. For the second time this year, I hope I don't make mistakes against Chelsea [on Wednesday].
"If we have the same spirit as we had in the second half we can win the next game against Chelsea. And I am confident for the Premier League because we stayed on top for seven months and now we are in second position, one point behind. I am very confident we can win the title.
"I think that now it will be a good fight until the end of the season because we have only the Premier League and we can put all of our strength into this. I think it will be good.''
Mancini joked that City followed United out of the competition to focus on their title bid. He said: "We were envious of United because they lost, so we wanted to lose this game!''
Mancini said of the Balotelli foul which put led to Sporting's opener: "I was disappointed with him when he conceded the free-kick, but it is not his fault we lost this game.''
Sporting coach Ricardo Sa Pinto never doubted his team had the ability to follow up last week's first-leg success. The former Portugal striker has overseen a transformation of fortunes since taking charge at the Jose Alvalade Stadium last month, winning six of his eight games in charge.
Sa Pinto said: "I am very proud to be the leader of this team and to have these players working with me. I said before, in the first leg and yesterday, that I believed in the team and the players.
"We knew Manchester City were a big team and for that I am really pleased to get through. It is great for the image of Sporting to knock out a team like Manchester City, who are one of the best teams in the world.''