West Ham manager Slaven Bilic does not expect any let-up from Chelsea in their march towards the Premier League title.
Eden Hazard and Diego Costa were on target as Antonio Conte's side prevailed 2-1 at London Stadium on Monday, with Manuel Lanzini netting a stoppage-time consolation for the hosts.
Chelsea lead second-placed Tottenham by 10 points and, even though Manchester City could shave that advantage to eight by beating Stoke City in their game in hand on Wednesday, Bilic identified a thankless task for the chasing pack.
"There is still a long way to go," he told BBC Sport. "They look serious, for me they are not going to lose that. I can't see them being casual."
West Ham started brightly before falling behind to a 26th-minute opener - Hazard scything them apart on the counter-attack after Mark Noble coughed up possession.
"They deserved to beat us. It's very simple," Bilic said. "If you want to beat Chelsea then you have to hope for their mistakes and use them.
"If it's the other way around and you make mistakes, they use them straight away and it's very hard. I'm disappointed.
"We were on top. We started well and created problems down the left but didn't have enough bodies in the box.
"Then we made a cheap mistake in a position where you can't lose the ball."
After Costa capitalised on some slack set-piece defending early in the second period, Bilic conceded his team regularly looked in danger of shipping further punishment.
"Second half again, a cheap goal," he added. "To be fair, all of their counter attacks looked dangerous."