LONDON (AP) Guus Hiddink was unable to inspire Chelsea to victory in his first Premier League match back in charge at Stamford Bridge, with Oscar missing a late penalty in the 2-2 draw with Watford on Saturday.
With both sides hunting all three points, Chelsea's Eden Hazard was tripped by Valon Behrami after a marauding run into the penalty area in the 80th minute.
Oscar stepped up but slipped in his run-up and blazed high over the crossbar.
''We wanted to win today,'' Chelsea midfielder Nemanja Matic told Sky Sports. ''It's not a good result for us, we are sad, we wanted three points. Oscar has to keep his head up because these things can happen. I'm sure he will score the next one.''
Chelsea is 15th in the Premier League standings after the draw, while Watford is seventh but moves level on 29 points with Manchester United, which occupies sixth on superior goal difference.
Diego Costa scored both of Chelsea's goals but picked up his fifth yellow card of the season for a foul in the 88th and will be suspended for his side's next match, against Man United, on Monday.
''Diego Costa showed his best today,'' said Hiddink, who was interim manager of Chelsea in 2009. ''It is a pity.''
Costa put Chelsea ahead in the 32nd minute, with an instinctive volley after John Terry won a header from Willian's corner.
But three minutes before halftime, Watford captain Troy Deeney hauled his side level with a penalty, sending Chelsea goalkeeper Thibaut Courtois the wrong way after Matic was penalized for handball.
Watford, heading into the match with four straight wins, was galvanized by the equalizer and soon forced itself into the lead.
Odion Ighalo was allowed to turn and run at goal by Gary Cahill in the 56th minute, and his left-footed shot deflected off the defender and looped beyond Courtois.
But Chelsea kept pushing to get back into the game, and Watford's lead was short-lived.
Costa notched his second with a composed finish that conjured memories of the striker in action for Chelsea last season, when his 20 goals propelled the club to the league title.
There were claims of offside from the Watford defense as he ran through to reach an ambitious pass by Willian, before taking one touch to control before lashing across Heurelho Gomes and into the far corner.
Both sides were unhappy to settle for a point, but the best chance either had for victory was Oscar's spot kick.
''It was tough to play against Chelsea but I'm very happy with the point,'' Watford manager Quique Sanchez Flores said. ''I think the team has enough confidence for the future, it's amazing for the story of Watford.''