Everton shook off last week's derby disappointment to thumped UEFA Cup opponents Larissa 3-1 at Goodison Park tonight.
Leighton Baines and Steven Pienaar combined well down the left to tee up Osman who drilled in a sublime second.
Silva Cleyton punished Joleon Lescott's mistake for Larissa but Victor Anichebe sealed it with a fine run and finish.
Cahill was superb throughout his 65-minute run out and gave Everton's midfield a edge that had been missing since he broke his metatarsal against Sheffield United last season.