West Ham United co-chairman David Sullivan has warned manager Slaven Bilic that he and his side must improve following their 3-2 defeat at Bournemouth on Saturday.
Sullivan expressed his frustration after the Hammers were left without a win in four matches as they left the Vitality Stadium empty-handed.
Joshua King netted a hat-trick, including a 90th-minute winner, to secure the Cherries' first victory of 2017 after he and Benik Afobe had both missed from the penalty spot.
"I was very disappointed and frustrated with the manner of our defeat at Bournemouth on Saturday," Sullivan told the club's official website.
"We went down there determined to bounce back from the Chelsea defeat on Monday, but we didn't play as well as we know we can. Slaven, the players and the staff all know we have to do better.
"We have conceded too many goals early in halves in recent games and, while we've managed to get ourselves back into games like the ones at Southampton and Watford and at home to West Brom, there will be matches where we cannot equalise. That situation cannot go on.
"I am sure that Slaven, his backroom staff and the team were not happy with what happened and they will think about it a lot over the next few days."
West Ham welcome Premier League champions Leicester City to the London Stadium on Saturday.
