Chelsea face a stern test of their English Premier League title credentials when they meet Arsenal in a London derby at Highbury tomorrow (10pm, ESPN). Chelsea drew 0-0 at Birmingham City on Tuesday to steal top place from Arsenal. The Blues have won six and drawn two of their first eight games under Russian billionaire owner Roman Abramovich, who has transformed the club now known by fans as 'Chelski'. His money has funded superstar signings including Argentina's Hernan Crespo and Juan Sebastian Veron, Romanian striker Adrian Mutu, England's talented youngster Joe Cole, tough-tackling French midfielder Claude Makelele, and tricky Irish winger Damien Duff. The Gunners, runners-up last year and champions in 1998 and 2002, have been through a turbulent period recently. They've had many disciplinary problems including the ugly scenes at the end of their match with Manchester United at Old Trafford last month. They struggled in their opening two European Champions League matches - losing 3-0 at home to Inter Milan, and drawing 0-0 at Lokomotiv Moscow. But things improved in their last game when Robert Pires scored a stunner in a 2-1 win over Liverpool at Anfield. In other Premier League matches tomorrow, Leeds play Manchester United (7pm, ESPN), and Portsmouth take on Liverpool (10pm, STAR). On Sunday, a feisty midlands derby is expected when Aston Villa clash with Birmingham ((7pm, ESPN).