Costa winner was wonderful, concedes Pulis
The Baggies boss expressed his admiration for the Chelsea striker's 12th goal of the season but was disappointed to see his side's hard work undone by a Gareth McAuley error.
West Bromwich Albion boss Tony Pulis was frustrated to see one mistake cost his side an impressive result against Premier League leaders Chelsea, but conceded Diego Costa had scored a "wonderful goal" to beat them.
Costa struck with just under 14 minutes remaining to give Chelsea a 1-0 win at Stamford Bridge on Sunday, their ninth consecutive top-flight victory to return them to the summit.
But the striker's curling winner only arrived after a mistake from Baggies defender Gareth McAuley, with Pulis ruing how close his team had come to a surprise point after working all week to devise a plan that countered the hosts' 3-4-3 system.
"The goal was disappointing because Gareth should have dealt with it, but I have got no qualms with him," said Pulis, whose side lost for the first time since October.
"To get beat by that one mistake – and it's a wonderful goal from Costa – is so disappointing, but we move on.
"Our structure and organisation was very good. One mistake, one chance and the fella puts it away – that is the difference in quality that separates the teams at the top.
"It is disappointing because Gareth has got to deal with it. He's made a mistake and we move on. We don't really want to criticise anyone.
"They are a very hard working group of players – I'm very disappointed for them. Our supporters will go home very disappointed, but having watched a very honest, hard-working team that very nearly pulled it off.
"I was happy all the way through the game. They play a different shape system to most teams in the Premiership. We had a good week to work on it. We were well set up without possession and caused them some problems on the break, particularly in the first half".
The defeat leaves West Brom eighth in the table ahead of their next match at home to Swansea City on Wednesday.