West Ham rout Chelsea Arsenal lose
Champions Manchester City moved top of the Premier League table, for a couple of hours at least, after Carlos Tevez earned them a 1-1 draw at home to Everton, although Manchester United will open a three-point lead if they win at Reading later.
Juan Mata gave Chelsea a well-deserved lead but West Ham roared back to pile pressure on Benitez with former Chelsea striker Carlton Cole levelling just past the hour before substitutes Mohamed Diame and Modibo Maiga struck late on.
Benitez, whose appointment in the wake of Roberto Di Matteo's sacking has proved unpopular among fans, is the first Chelsea manager not to win any of his first three matches in charge since Russian oligarch Roman Abramovich bought the club.
"In the second half we didn't start well, they got on top of us and we couldn't manage," former Liverpool manager Benitez, whose first two matches in charge ended in 0-0 draws against Manchester City and Fulham, said.
The European champions, now without a win in seven league matches having topped the table, remain in third spot on goal difference from Tottenham Hotspur, who joined them on 26 points with a 3-0 victory at Fulham -- Jermain Defoe scoring twice.
West Bromwich Albion slipped to fifth, also on 26 points, after a 1-0 defeat at home by Stoke City.
Arsenal were booed off at the Emirates as they slipped to 10th following Michu's late double for Michael Laudrup's impressive Swansea, which took the 2 million pound summer signing's tally for the season to 11.