Premier League leaders Chelsea would have won their game against Burnley 99 times out of 100, said boss Thomas Tuchel as they let the Clarets "steal a point by pure luck".
Kai Havertz opened the scoring for Chelsea with a header from Reece James' cross, only his second league goal this season.
The Blues could have scored a hatful with Thiago Silva's header hitting the post, while Nick Pope saved well from Callum Hudson-Odoi in each half.
But Burnley levelled when Ashley Westwood whipped in a cross which Jay Rodriguez headed across to Vydra to stab home.
"That's why everyone loves the game - a team can steal a point if the other team forgets to score the goals they deserve," Tuchel.
"We played a fantastic match. Of course I'm disappointed.
"If we played this game 100 times, we'd win 99 times. Today we didn't win it. The second goal would have decided it. It's always possible you miss one ball, one cross, and this can happen.
"It's our fault. We should have scored. We created so many chances.
"You have the opponent where you want to have them. You create so many chances. We let them believe it was possible to steal a point by pure luck and that's what happened."
Chelsea are three points clear of Manchester City at the top of the table, while Burnley remain in the relegation zone.