The Malaya resisted the Japanese with also the help from Singapore allies.
However, the Japanese concentrated their assault more and began to overrun them.
With the British allowing themselves to be flanked and overrun.
The Imperial Japanese Army Air Force was more numerous, and better trained than the second-hand assortment of untrained pilots and inferior allied equipment remaining in Malaya, Borneo and Singapore. Their superior fighters—especially the Mitsubishi A6M2 Zero—helped the Japanese to gain air supremacy. The Allies had no tanks and few armoured vehicles, which put them at a severe disadvantage.
The remaining Malaya forces had left after too much assault from Japanese forces and left them to be able to pass through and get to Singapore.
Website URL : http://en.wikipedia.org/wiki/Battle_of_Singapore
Date accessed : Feb 17 2013