Unseeded Vijay Kannan upset fourth seed Aqeel Khan of Pakistan after a marathon battle to move into the semi-finals in the US $10,000 Indian Oil ITF Men's Futures tennis tournament in Delhi on Thursday.

Kannan needed two hours and 24 minutes to quell the challenge of Aqeel, winning 6-1, 7-6 (7/5), and will face Chris Kwon of the United States for a berth in the summit clash.

Kwon, who will be playing his second successive semi-final, thrashed wild card Sanam Singh 6-4, 6-1.

In the other quarter-final matches, fifth seed Vinod Sridhar packed off third seed Vishal Uppal 7-5, 6-3 while second seed Sunil Kumar Sipaeya defeated Jaco Mathews 6-1, 7-6(7/4).

Kannan, who had accounted for sixth seed Mustafa Ghouse in the first round, was undeterred by the late start due to rain and raced to a 3-0 lead, breaking Aqeel's serve in the second game.

He went on to break his opponent again in the sixth and then served with precision to pocket the first set.

With Kannan breaking Aqeel in the first game of the second set, it looked like early curtains for the Hyderabad-leg winner but the Pakistani national champion fought back to level scores at 2-2 before breaking his opponent's serve in the seventh game to take the lead.

The Indian broke back immediately and then made it 5-4 in the ninth and looked poised to wrap up the match.

But it was not to happen. Though Kannan earned two match-points, Aqeel came up with some fine baseline play to force the set into the tie-breaker.

Kannan had some tricks up his sleeves for the tie-break as he made some fine volleys and set up his third match-point with an ace to wrap up the second set, which lasted an hour and 42 minutes, and the match.

Former National hardcourt champion Vinod Sridhar once again showed that he has the knack of coming up with great winners on crucial points as he got the better of local favourite Uppal in one hour 19 minutes.

Both the players looked comfortable with their serves but Sridhar, who was able to break his opponent once in each set, finally emerged victorious.

Second seed Sipaeya played better tennis than he had in the earlier two days and considering the form shown by his semi-final opponent Sridhar in today's match, he will have to come up with a far better performance tomorrow.