Antonio Conte's men were in search of a positive result, with their opening Premier League match against West Ham looming large on 17 August (AEST).
And goals from Eden Hazard, Ocasr – the Brazilian's third in the space of a week - Diego Costa and Pedro did the job, although ex-Chelsea striker Claudio Pizarro and substitute Lennart Thy did notch for the host.
In a match that saw N'Golo Kante make his inaugural start for his new club since joining from Leicester City, Hazard was also named in a Conte starting XI for the first time.
Bremen had already played seven friendly matches going into the game, but any superior match practice was not evident, as the visitors flew out of the blocks.
Hazard was allowed to find the bottom corner for Chelsea with merely seven minutes gone, after being gifted far too much space on the edge of the penalty area by Zlatko Junuzovic.
Two minutes later, Conte's men found themselves two up, with Hazard again playing an important role. The Belgium winger drove down the left before finding Oscar in the box and he played a neat one-two with Diego Costa before stabbing in a low finish.
After striking the crossbar early on, Junuzovic atoned for his error by winning a penalty from Nemanja Matic on 32 minutes, with Pizarro slotting home an inch-perfect spot-kick to reduce the deficit.
But just before the break, Costa was slipped in behind enemy lines by Hazard, before keeping his cool to slot a neat finish across goal to restore Chelsea's two-goal cushion.
Bremen's Thy made an impact from the bench with a stunning strike from 25 yards on 65 minutes, Thibaut Courtois only able to offer a despairing dive.
Conte took no chances in immediately substituting captain John Terry after a late injury scare caused by a collision, before Pedro ensured it was all smiles again with a stoppage-time strike to seal the win.