Arsenal manager Arsene Wenger was left to rue his side's 1-0 defeat against Chelsea at the Emirates Stadium Sunday evening.
The Gunners, who prior to kick-off occupied second place in the Premier League table, suffered a blow to their Premier League aspirations as their London rivals won with a goal from Diego Costa who was fouled by Per Mertasaker and a consequent red card to the defender, five minutes before his 23rd minute goal.
The German defender was red-carded by referee Mark Clattenburg as he was the last defender chasing the former Atletico Madrid striker.
The defeat leaves last season's FA Cup winners, who take on Championship side Burnley in their next outing, in third place in the table – three points behind shock leaders Leicester.
Wenger, 66, was disappointed with the result, which extends their winless run against the Premier League champions to six games, and reckons his side deserved at least a point for their efforts.
"It's a shame to put so much an energy into the game come out without the points," he said.
"I thought we should've come out with the game with at least a 1-1 even though we were down to ten men.
"We had many opportunities, maybe not clear-cut but you think one of them we should take.
"That's the regret that the team put in so much energy and you don't come out with any points," Wenger admitted.