Geremi marked his first appearance in a Chelsea shirt with the winner in the pre-season friendly at Crystal Palace.
Dougie Freedman's lobbed shot had levelled matters after Mikael Forssell had opened the scoring for the Blues.
But then up stepped Geremi, a £7million signing from Real Madrid, with a sweet free-kick shortly before half-time to secure a 2-1 win for Claudio Ranieri's expensively assembled team.
Paul Merson returned to haunt his former club Aston Villa as his new employers, Walsall, scored a notable West Midlands derby win at the Bescot Stadium.
Merson, who joined the Saddlers in a shock move from Portsmouth after helping the south coast club to the First Division title, hit a rising shot after Jorge Leitao headed the ball into his path.
Darius Vassell equalised for the Premiership side but Gary Birch hit the winner for Walsall.
Kanu secured a 1-1 draw for Arsenal at Parkhead after Liam Miller had opened the scoring for Celtic with a sweet strike.
Nicolas Anelka scored twice, including a penalty, as Manchester City put neighbours Oldham to the sword with a 6-0 win at Boundary Park. Summer signing
Trevor Sinclair, Robbie Fowler, Shaun Wright-Phillips and Paulo Wanchope scored the other goals for City.
Goals from Juninho, Szilard Nemeth and Jonathan Greening preserved Middlesbrough's excellent pre-season form in the 3-2 win at Sheffield United - despite two fabulous long--range strikes from highly-rated Blades midfielder Michael Tonge in reply.
David Dunn was on the mark as Birmingham drew 2-2 at Burnley.
Geoff Horsfield opened the scoring after Graham Branch's backpass proved too short but the Clarets levelled when Ian Moore was set up by Alan Moore. Dunn, booed by the home fans following his summer move from Blackburn, put Birmingham back in front following a surging run into the box.
But Robbie Blake equalised from the spot after Ian Moore had been brought down by Kenny Cunningham.
Blackburn lost 1-0 at First Division new boys Wigan thanks to Lee McCulloch's powerful volley.
Fulham twice took the lead against Motherwell thanks to goals from Louis Saha and Steve Marlet, but Alex Burns' double - the first from the penalty spot - ensured matters ended even.
Wolves' awful pre-season continued as they were beaten 2-1 at Coventry. The Premiership newcomers fielded new signings Jody Craddock and Silas, with Steffen Iversen and Isaac Okoronkwo on the bench. But Dele Adebola turned Denis Irwin before opening the scoring and Calum Davenport added a second.
Kevin Cooper pulled a goal back with a long-range shot.
Simon Johnson and Jamie McMaster were on target for Leeds as they won 2-1 at Chesterfield.
David Johnson continued his prolific form of last season with four goals as Nottingham Forest won 6-1 at Rushden & Diamonds.