Graeme McDowell shot the lowest score of the day in Memphis but no-one was able to reel in runaway winner Brian Gay at the St Jude Classic. McDowell shot a seven-under-par 63 at TPC Southwind on Sunday night to claim a top-10 finish at 11 under par.

American Gay, though, was unstoppable as he continued his dominance of the event for the fourth round in succession, running out a five-shot winner at 18 under for the week and sealing his ticket to next week's US Open.

Gay, who won the Verizon Heritage tournament in April by 10 strokes, began the day at 14 under, one shot ahead of fellow American Bryce Molder with Australia's Robert Allenby another stroke back.

The lead was soon being extended, however, as Gay birdied the par-four second and then the par-three fourth, which Molder bogeyed.

Gay gained a further advantage at the par-four sixth to move to 17 under, leaving Molder at 12 under with 2007 winner Woody Austin, Heath Slocum and David Toms on 11 under heading to the turn.

Gay, though, bogeyed the par-four seventh to cut the gap between him and the field to four shots before a run of birdie-bogey-birdie between nine and 11 restored the five-shot lead.

Steady par golf all the way home, capped with a birdie at the 18th, sealed victory with a final-round 66, his third in a row following an opening 64.

Molder finished with a level-par 70 in a tie for second place at 13 under with Toms, who closed with a 65.

Australia's John Senden shot a 64 to move into a tie for fourth with Paul Goydos and Allenby, who recovered from a shaky, four-bogey, two-birdie front nine to record a 69.

The field had been forced to wait four hours before the final round could get under way at TPC Southwind after an unexpected storm hit the Tennessee course on Sunday morning.

Even with players grouped in threes and playing from split tees for the final 18 holes, the pressure was on to complete play as more severe weather was expected during the late afternoon, prompting fears the final round would extend into Monday morning, when many of the field would be hoping to begin practice rounds at New York's Bethpage Black ahead of the US Open.

Luckily the bad weather held off long enough for even the leaders to get their rounds played but Northern Ireland's McDowell was long finished by then, having recorded a bogey-free round featuring an eagle at the par-three 16th and five birdies.

"It's always nice to post a low one on Sunday," McDowell said. "My game's been bubbling nicely for the last month or so and I just really haven't put it all together.

"So it was nice to come on a big of a late flurry and hopefully post a good finish."

McDowell claimed a tie of seventh place for his best finish in America since 2005, when he placed tied for second at Bay Hill and tied for sixth at the WGC-American Express Championship.

For Gay, celebrating his second win of the year, it was a sweet moment after a difficult day.

"It was a long course today, even longer than yesterday, really wet and didn't play into my hands at all," Gay said.

"I wasn't happy with all the rain but I managed to get it done. It's been a really great week and I'm really happy."