The Blues made it four consecutive wins in all competitions with a 4-1 victory over Southampton at St Mary's on Sunday afternoon thanks to goals from Tammy Abraham, Mason Mount, N'Golo Kante and Michy Batshuayi.
Chelsea have 14 points and are two off second-placed Manchester City - after the champions' shock home defeat to Wolves - but trail Liverpool by 10 after eight fixtures this term.
It is an excellent return for the Blues, who were unable to sign any new players during the transfer window, and are going through a transitional period with a young squad and new manager.
Lampard actually believes they could be doing even better but is happy with the position they are in, and believes with the same commitment, they can stay there.
"I am happy we are in and around the (top) group. Obviously Liverpool are out on their own at the minute, but at this early stage we are in a nice position," he said after the Saints win.
"This should give us determination to go away (for international duty) and come back in the same vein because the minute you relax in this league it can all change very quickly.
"The reason we are playing well is because of how hard we are working and how together we are. If we can keep that going, then we will be challenging right up there I hope."
Abraham opened the scoring on the south coast with an excellent lob over Angus Gunn after racing on to Callum Hudson-Odoi's fine through ball in the 17th minute.
Portsmouth-born Mount doubled their advantage seven minutes later, curling home before cupping his ears to the Southampton supporters, before Danny Ings pulled one back.
Kante's deflected effort put the Londoners 3-1 ahead at half-time and substitute Batshuayi drilled through Gunn's legs with a minute left - after Christian Pulisic's excellent through ball - to conclude the scoring.