Chelsea coach Roberto Di Matteo believes that the European champions must prove their worth this season without their former striker Didier Drogba. After an eight-year stay at Stamford Bridge, the Ivorian hitman departed this summer for Chinese club Shanghai Shenhua. The Blues will play with Arsenal on Saturday for the first time since the 34-year-old's departure. Earlier this week, Arsenal coach Arsene Wenger admitted that the absence of Drogba will be a kind of relief for his team. "Didier Drogba has been a fantastic player for this club for many years, but we have to move on from that," Di Matteo was quoted as saying by Sky Sports late on Friday. "That's the past. We're looking to the future now," he added. Drogba helped the west London club win three Premier League titles, four FA Cups, two League Cups and finally, the UEFA Champions League. Chelsea are now leading the Premier League table with 13 points, one ahead of second-placed Manchester United. (For more sports news and updates, follow Ahram Online Sports on Twitter:@AO Sports and FacebookAhramOnlineSports)