Ji Dong-Won grabbed a brace as Korea Republic outclassed India at a wet Al Gharafa Stadium to set up a mouth-watering AFC Asian Cup quarter-final against Iran.

Koo Ja-Cheol and substitute Son Heung-Min also found the back of the net for South Korea, but Cho Kwang-Rae's men will be left kicking themselves after wasting a hatful of clear-cut chances which condemned them to second place in Group C on goal difference thanks to Australia's 1-0 win over Bahrain.

Their profligacy could prove costly for the Taeguk Warriors with the Socceroos now set for the seemingly easier last-eight tie against Iraq, United Arab Emirates or Korea DPR.

The South Koreans took the lead after just six minutes when goalkeeper Paul Subrata could only push Lee Chung-Yong's cross into the air and Ji nodded in unchallenged from six yards.

Koo doubled his side's advantage with his fourth goal of the tournament three minutes later when India failed to deal with Cha Du-Ri's ball in from the right and Ji cushioned a cute header into the path of the striker, who rounded Subrata.

India halved the deficit in the 12th minute when Kwak Tae-Hwi brought down Sunil Chhetri in the box as they contested a long ball and the forward sent Jung Sung-Ryong the wrong way from the spot.

Kwak saw a header from Ki Sung-Yeung's corner cleared off the line before South Korea restored their two-goal advantage in the 23rd minute with a beautifully-worked effort.

Koo held off an Indian defender on the edge of the area before playing a delightful reverse ball that freed Ji and he coolly lifted the ball over the advancing Subrata.

The striker was then left wondering how he did not complete his hat-trick ten minutes before half-time.

Subrata let Ki's corner slip through his hands and the ball fell to Ji six yards out. His initial shot was blocked by Syed Rahim Nabi and his follow-up struck the same player lying prone on the floor. The frontman's third effort was then headed off the line by Surkumar Singh from close range.

Subrata denied Son with an outstretched leg before the substitute came agonisingly close to the Koreans fourth goal in the 64th minute when Lee's low cross reached the forward at the far post, but his first-time effort struck the upright and was cleared.

From the subsequent corner, Deepak Kumar Mandal cleared Hwang Jae-won's header off the line.

Ji lifted a shot over the bar from 12 yards with Subrata out of position before Son finally claimed Korea Republic's fourth goal with nine minutes to go when he rifled home via the underside of the bar after collecting Koo's pass on the left side of the box.

There was still time for Son to hit the bar before Chhetri brought a smart double save out of Jung in a rare India foray forward.