Manuel Pellegrini blamed a lack of recovery time after watching Manchester City limp to a 3-0 loss at Liverpool that could have effectively ended their Premier League title aspirations.
A lacklustre display from the visitors was punished at Anfield as Liverpool gained a measure of revenge for Sunday's League Cup final defeat on penalties.
Wednesday's contest was City's third match in seven days across three different competitions, with Pellegrini having taken his side to Ukraine in the Champions League prior to their Wembley triumph.
"It is difficult to have an excuse, but I saw the team was not recovered from the last week," the Chilean told BBC Sport.
"We played Champions League and then League Cup final and I saw team was not fresh and Liverpool played better.
"The last two days we work very light, just try to recover the players but from beginning they won all the balls and had a high pace – more pace than our team.
"We didn't attack well and create chances and didn't have fresh legs to play like we can."
The result left City 10 points behind leaders Leicester City with one game in hand, but Pellegrini has not given up hope of ending his tenure with another title.
He added: "It seems like the Premier League continues being the same from the start and very close. We will continue fighting."
Goals from Adam Lallana, James Milner and Roberto Firmino did the damage on Merseyside.
