Cesar Azpilicueta admitted that Chelsea only had themselves to blame after a 2-1 defeat to Manchester United at Old Trafford.
Willian fired the Blues into the lead on 32 minutes, but Romelu Lukaku pulled United level before half-time and Jesse Lingard headed in the winner with 15 minutes remaining as Jose Mourinho dealt Antonio Conte a serious blow in the race for a top-four finish in the Premier League.
Conte was widely criticised for substituting Eden Hazard shortly before Lingard's winner but, speaking to SFR Sport after the match, Azpilicueta insisted that Chelsea's problems had been collective rather than individual.
"I think we played well in the first half," he said. "We conceded that goal to take it to 1-1, and in the second half we didn't control it as we wanted to, as we had done in the first half, and we were punished with that second goal.
"They scored one more goal than us. It's a big game and in matches like that you have to be ready at every moment. Today we weren't lucky enough to get the three points."
A seventh Premier League defeat of the season leaves Chelsea fifth in the table, two points adrift of fourth-placed Tottenham after 28 matches. They take on runaway leaders Manchester City at the Etihad Stadium on Sunday.
Another setback could leave Chelsea with too much ground to make up in the final stretch of the season, but Azpilicueta is not giving up yet.
"We knew the battle was going to be tough," he added. "We'll keep going, there are still a lot of points to pick up. We have to keep working hard."