The world no 1 totally outclassed the Turkish qualifier, completing victory in under an hour to set up a semi-final clash with fourth seed Tomas Berdych.
Returning from his Australian Open triumph, Djokovic is yet to drop a set in this tournament and he seized an early break with a slashing forehand pass.
Ilhan ousted sixth seed Fernando Verdasco in the previous round, but was unable to gain a foothold against the Serb, overhitting a forehand to concede another break.
There were sympathetic cheers when Turkey???s no 1 finally got off the mark in the first set, but Djokovic quickly served himself into a 1-0 lead.
Ilhan raised brief hopes of a fightback when he held break points at 1-0 up in the second, prompting a gritty response from Djokovic, who repelled a number of attempts to steal his serve. ????
A trainer was called to administer treatment to Ilhan???s back, but he continued to wilt under Djokovic???s relentless returns and his quickfire defeat was sealed by a forehand into the net.??