Bertrand Traore opened the scoring after six minutes with a tidy finish before De Bruyne rifled in a truly brilliant volley, but turned his ankle and appeared to hurt his knee in the process.
Romelu Lukaku added a third in first half stoppage time and Victor Moses, one of 11 Chelsea substitutes, added a late fourth before Fadhli Shas gave the home fans something to cheer about with an injury time consolation.
As expected, Chelsea were dominant from the outset and it took them barely six minutes to move ahead. De Bruyne created it with a good cut back from the right and Traore stroked in from 12 yards without breaking stride.
Chelsea, fielding new signings Mark Schwarzer and Marco van Ginkel, were comfortable and Traore could have notched up his second of the match, but saw his early shot saved.
Malaysia created a couple of half chances that were enough to force Chelsea coach Jose Mourinho to the edge of his technical area.
But Chelsea steadied the ship and moved 2-0 ahead in stunning fashion. Latching onto a long ball that was flicked on by Lukaku, De Bruyne found the net with an explosive volley that underlines the young Belgian's abundant talent.
But in the act of scoring such a wonderful goal - his first for Chelsea - De Bruyne injured himself and was stretchered off holding his knee, after turning his ankle.
Malaysia enjoyed another good spell but couldn't find the net, which Chelsea did again on the stroke of half time, this time with Lukaku finishing well after Traore had rolled the ball into his path.
Mourinho made wholesale changes at the break, and Demba Ba could have added a fourth when he cut inside from the left and drilled a very good shot at goal, which the keeper shovelled away for a corner.
Eden Hazard, one of the two survivors of the half time cull, almost scored a rare headed goal, but saw the ball glide the wrong side of the post after Moses picked him out.
Chelsea lacked the fluidity of the first half but eventually added a fourth in the last minute when Moses squeezed a powerful low drive inside the near post, with the Malaysia keeper at fault.
Malaysia raised the roof in injury time when Shas headed in a consolation after Chelsea failed to clear a free kick.