Manchester City boss Roberto Mancini blamed too many games for their lacklustre victory over relegation threatened Wigan at the Ethiad Stadium.
Carlos Tevez struck late on to give the hosts a 1-0 win against unlucky Wigan in their FA Cup final dress rehearsal.
Argentine striker Tevez netted his 11th league goal of the season seven minutes from time to narrow the gap to 13 points between City and Premier League leaders Manchester United, who only drew at West Ham.
But after succesive victories against city-rivals United at Old Trafford and Chelsea at Wembley, Mancini felt his squad were running on empty.
The Italian told Sky Sports: "It was hard work because we were so tired because we played two important games in five days and we played the last game three days ago.
"It was a difficult game but we knew this before the game. Wigan play good football, they play really well.
"Wigan played well every time they want to play to win because they have a good manager."
And when asked about Tevez winning goal, Mancini said: "He's a top quality player and he played very well. He scored a fantastic goal.
"I think we didn't play well for 65 minutes. Instead the last 25 we played very well, scored a goal and created chances."
And the City boss feels confident that the Latics will remain in the Premier League come the end of the season.
"I think they will stay up because I'm sure they will do a good job from now until the end. They play very well and Roberto Martinez deserves to stay in the Premier League."