But there was disappointment for Australia's Mark Hensby, who had started the day as co-leader with Harrington and Cink.

He had hoped to mark his 54th birthday in style  but could not conjure any of the magic that led to 19 birdies over the first three days and a share of the lead. 

Aiming to become just the second Aussie to win the event after Graham Marsh in 1997 and the first to win a senior major championship since Stewart Ginn at the 2002 Senior Players Championship, he only made two birdies on Sunday.

He shot a three-over 73 to tie for fourth at five under with Thomas Bjorn.

Playing alongside Cink for the fourth straight day, Harrington shot a three-under 67 to finish on an  11-under 269 on the tricky, heavily sloping Broadmoor course.

The Irishman sealed the match by hitting his approach to eight feet on No.18, putting pressure on Cink, who trailed by one but sat 30 yards in front of him on the fairway.

Cink's approach landed on the precipice of a ledge, but spun backward and did not come to rest until it was 35 feet away to set up a two-putt.

That made it advantage Harrington, who also two-putted to win his second US Open title in four years, adding that to a trophy case that also includes the 2007 and '08 British Opens and the 2008 PGA. 

The only player who threatened to get in the mix in this two-man show was Miguel Angel Jimenez. After opening with bogey, Jimenez made eight birdies to pull within a shot of the lead. 

But he yanked his tee shot well left on No.18, had to punch out and made bogey. He still shot the best round of the tournament, a six-under 64, and finished in third, two shots back.

Of the other Aussies, Cameron Percy finished joint ninth, Scott Hend was equal 16th, Greg Chalmers shared 18th while Steve Allan and Rod Pampling tied for 22nd.

Stuart Appleby finished joint 32nd, with Richard Green 45th.