Unai Emery maintained his strong start at Aston Villa, overseeing a victory at Tottenham Hotspur which stopped the north Londoners from returning to the top four.
Spurs goalkeeper Hugo Lloris, who made his first start after losing the FIFA World Cup final to Argentina, was at fault for the opener, fumbling a shot in the 50th minute, allowing Argentinian Emiliano Buendia to score.
It was the seventh league match in a row that Spurs had gone 1-0 down and, as with the past six times, they went on to concede another.
Douglas Luiz ran on to an incisive pass from John McGinn to double the lead with 17 minutes remaining.
Emery has now won three of his first four matches in charge, and has become the first Villa manager or head coach since 1998 to win his first two Premier League road trips. Villa are up to 12th on 21 points.
Antonio Conte’s side have dropped to fifth over the weekend with 30 points, being overtaken by Manchester United.
Chelsea’s top-four hopes also suffered a setback as they were held to a 1-1 draw at Nottingham Forest.
The Blues looked in control in the first half after taking the lead through Raheem Sterling’s fourth goal of the season.
But Forest were rewarded for a more enterprising approach in a second half in which they produced nine attempts on goal to Chelsea's one, and they levelled through Serge Aurier’s fine chest and volley on 63 minutes.
Chelsea, who have mustered only one win in seven Premier League matches, are in eighth place on 25 points, 18 adrift of leaders Arsenal and seven behind fourth-placed Man Utd.
Forest, unbeaten in five home league matches, rise to 17th on 14 points.
On Monday, sixth-placed Liverpool can leapfrog Spurs with a victory when they visit Brentford.
The Reds are looking for a fifth straight win, but their hosts are unbeaten in five matches, with that run including a victory at Manchester City and a home draw against Spurs.