"We tried to keep the ball second half and contain them, but they're a fine side, they threw caution to the wind because they had nothing to lose".
Chelsea, who had club captain Gary Cahill and Cesc Fabregas sent off, trailed 3-0 at the interval, and despite finding a route back into the match in the second period, Burnley held on for their first ever Premier League victory at Chelsea.
There was no such nonsense from Antonio Conte, but he must be regretting his comment last month when he said "wants to avoid a Mourinho season", referring to the 2015 meltdown.
"I think that the coach, the players and referee can make mistakes". Chelsea's hierarchy are well aware of the current squad situation and the expectation is that three or four more players will arrive before the close of the transfer window.
Morata had just 30 minutes to somehow help spark a revival from three-goals down and pulled one back in the 70th minute with a neat header, diving in to nod Willian's cross into the far corner.
Costa was often praised last season not as Chelsea's top scorer and biggest goal threat, but as the "point of reference" for the entire attack.
Burnley made it 3-0 before half-time when Vokes headed in Defour's free-kick.
Wayne Rooney crowned his first appearance for formative club Everton since 2004 by notching the victor in a 1-0 win over Stoke City, heading in Dominic Calvert-Lewin's cross for his 199th Premier League goal.
Ahmed Hegazi scored in his debut for West Brom, on loan from Egypt's Al Ahly.