Manuel Pellegrini has admitted that West Ham lacked intensity as he watched his side succumb to a 2-0 loss at Burnley on Sunday.
The Hammers were dominated by their opponents, as first-half goals from Chris Wood and Dwight McNeil inflicted just a second league defeat in seven away matches - leaving them eight points off Manchester United in the last Europa League spot.
Speaking post match to the media, via West Ham's official website, Pellegrini was left visibly frustrated at the lack of recovery time.
"It was frustrating because we wanted to win this game and had the chance to be seventh," he said. "We lacked energy to win it. We had a flight that arrived at 2am in the morning after playing Southampton.
"I was happy until two o'clock today. This was a game we were able to win - Burnley was in a bad moment but they played with intensity. Burnley recovered better because they had 30 or 35 hour's more (rest)."
Despite being second best in large parts the Hammers rallied in the latter stages, with Andy Carroll coming closest - notably forcing a superb save from the Clarets' goalkeeper Tom Heaton to prevent the forward's first goal of the campaign.
Replacing Lucas Perez at half-time, the former Liverpool man was responsible for 45% of his side's attempts - and Pellegrini admitted his side improved after his introduction.
He added: “We improved a little bit after half-time, but we only had one clear chance and that was from the head of Andy Carroll.
"In defending, possession and attacking the team lacked energy. We improved a little bit more once we made changes."