* Arsenal earned first win over local rivals in seven league games
* Mustafi headed Arsenal in front after 36 minutes
* Sanchez doubled the lead before halftime
* Ineffectual Kane and Alli substituted for Spurs
* Arsenal at Burnley next, Spurs host West Brom
Nov 18 (Reuters) - Shkodran Mustafi and Alexis Sanchez earned Arsenal a convincing 2-0 Premier League win over Tottenham Hotspur in the north London derby at the Emirates Stadium on Saturday.
Mustafi opened the scoring with a superb 36th-minute header and Sanchez doubled the advantage five minutes later with a close-range strike.
The result lifted Arsenal to fifth place in the table on 22 points, one behind Spurs.
Arsenal have now won 11 Premier League matches in succession at their home ground after their first league victory over arch-rivals Spurs in seven games. (Reporting by Matt Westby, Editing by Ed Osmond)