Azhar Ali hit a dogged unbeaten century as Pakistan continued to build its lead and edge toward a clean sweep against a listless England on the third day of the third and final test Sunday.

Graeme Swann dropped a low catch in the slips when Ali was on 84 as Pakistan progressed to 295-3 at lunch - an overall lead of 253.

Ali is on 115 with captain Misbah-ul-Haq on 16 at the break.

Resuming at 222-2, overnight century-maker Younis Khan frustrated the England bowlers for another half an hour before he was trapped lbw by Stuart Broad.

Khan went for the DRS referral, but TV umpire Shahvir Tarapore upheld onfield umpire Steve Davis' decision as replays suggested the ball would have just clipped the bails.

Khan put on 216 runs with Ali in a third wicket stand that began before lunch on the second day.

He hit 12 fours and a six in his 20th test century and faced 221 balls in a superlative display of aggression and defense for just over five hours.

Ali, resuming on 75, square cut left-arm spinner Monty Panesar for his fifth boundary of the innings to raise his second test century off 319 balls.

England captain Andrew Strauss - looking to avoid England's first ever whitewash to Pakistan - had little answer to the batsmen on a wicket where Pakistan was bowled out for 99 and England was also restricted to 141 in its first innings.

Kevin Pietersen was the sixth bowler used by Strauss, but even his three overs of offspin could not bring a reward for the top-ranked test team.