Slaven Bilic has told his West Ham United side that Saturday's 2-0 defeat at Watford is "unacceptable", but claimed that they will bounce back to their high-flying best.

The Irons' seven-match unbeaten streak - which included wins over Liverpool, Manchester City and Chelsea - came to an abrupt halt as a brace from Odion Ighalo proved enough for the Hornets.

"It was a collective bad day. I told the players it was unacceptable and to make sure it was a one-off," he is quoted as saying by ESPN. "You are going to lose games in this league but we weren't good today, apart from in the first 10 minutes.

"We gave them the win. Watford were full of respect for us -- but when they smelt that we weren't penetrating enough, and that our movement and passes were slow and backwards, they smelt the opportunity to go at us.

"We learned a lesson, and I see no reason why we won't come back and play like we did before."

Bilic's men drop back to fifth in the Premier League table, one point behind fourth-placed Manchester United.