Vokes hooked in a scuffed finish under minimal pressure in the 24th minute as Chelsea players failed to react to Matt Lowton's cross.
They were expected to suffer another defeat when the fixtures list came out and they were scheduled to face league champions Chelsea at Stamford Bridge but things went off-script.
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SEAN Dyche felt his side deserved their opening day victory over champions Chelsea as he praised his players' mentality in the heat of the battle.
Disjointed and embarrassed in the first half, Chelsea threatened to mount the most unlikely of comebacks in a stirring second-half display, but just failed to overcome their numerical disadvantage.
The visitors were the better side overall with a disciplined, energetic and ruthless first-half display that saw them put three past the Blues, with Sam Vokes netting twice.
Huddersfield Town made a dream start to their debut season in the Premier League by beating Crystal Palace 3-0 away from home.
Chelsea fought back to score two goals, but were reduced to nine men when Cesc Fabregas was dismissed and were unable to net an equaliser.
Chelsea brought in Alvaro Morata in the second half and it paid off as the Spaniad got his first goal for the club to make it 3-1 in the 69th minute of the game.
Steve Mounie doubled their advantage with a powerful header and added a third in the 78th minute, as new Crystal Palace boss Frank de Boer endured a miserable first game.
"We're written off at the start of every season".
His replacement, £65m signing Álvaro Morata was mostly a bench-warmer for Real Madrid last season and there are serious questions surrounding whether he will have as much of an impact as the bullish Costa.
"But we're not getting carried away, it's a great result, brilliant for our players and supporters, but we know there's a big season ahead of us, and everyone is telling us it's a big challenge".