Chelsea head coach Carlo Ancelotti is optimistic that key midfielder Frank Lampard could be fit for Sunday's Premier League clash at Arsenal. Lampard has been sidelined with a thigh injury he sustained during international duty with England. But Ancelotti is hopeful Lampard could start the fixture when the Blues face London rivals Arsenal at the weekend. The Italian told Sky Sports: "He is working very well and trained well today. He could start the game." Ancelotti was speaking after his side's 1-0 win over Porto which sealed their position at the top of UEFA Champions League Group D.