Guus Hiddink's first Premier League match back in charge of Chelsea ended in a 2-2 draw against Watford after Oscar missed a penalty in the 80th minute at Stamford Bridge on Saturday.
With the score level, Eden Hazard was tripped by Valon Behrami. Oscar stepped up, and slipped in his run-up before blazing over.
Diego Costa gave Chelsea the lead with a volley after John Terry won a header from Willian's corner in the 33rd minute.
Troy Deeney leveled with a penalty three minutes before halftime, sending Thibaut Courtois the wrong way after Nemanja Matic's handball.
In the meantime Leicester lost its first Premier League game since September in a 1-0 defeat at Liverpool on Saturday.
Substitute Christian Benteke struck in the 64th minute against the league leaders at Anfield, steering home a pass across goal by Roberto Firmino with a controlled finish.
Liverpool dominated the first half, with Philippe Coutinho and Divock Origi going closest for Juergen Klopp's team.
But striker Origi hobbled off injured after a promising 35 minutes, appearing to point to his hamstring. Benteke replaced him in Liverpool's attack.
N'Golo Kante almost scored for Leicester by turning a cross from Christian Fuchs toward goal, only for Simon Mignolet to make a good low save.
The defeat was Leicester's first since losing 5-2 to Arsenal on Sept. 26.