Justin Leonard birdied the second hole of a play-off to win the St Jude Championship in Tennessee.

Leonard, who also won this event in 2005, needed the extra holes to defeat Masters champion Trevor Immelman and Robert Allenby - after all three finished at four under for the tournament.

The American started the day three shots off the pace in this final PGA tour event before the US Open - in which Ireland's Padraig Harrington (68), Spain's Sergio Garcia (66), Boo Weekley (68) and Alex Cejka (70) all finished one shot off the play-off, on 277.

Leonard took a one-stroke lead with a birdie at the 15th, but a wayward drive on the 17th led to a bogey - and he also slid a 15-foot birdie putt just over the lip on the 18th.

In the play-off, Leonard dropped in a 19-foot birdie putt and then clinched victory when Immelman missed from eight feet closer.

Immelman had made consecutive birdies on the final three holes - making up for his double-bogey on the par-five third.

Allenby started with a bogey at the first but then posted six birdies en route to a 65 that put him in the clubhouse lead.

Australian Gavin Coles, playing behind Leonard, was tied for the lead on the 18th tee but double-bogeyed to miss out.

Tim Clark started the day two shots clear of the field but could not sustain his challenge.

Vijay Singh grabbed a share of the lead after eight holes but fell apart with back-to-back bogeys and then a triple-bogey at 12 - before coming back with three birdies to finish one under.

Collated final-round scores & totals: (USA unless stated, par 70):

276 Justin Leonard 68 73 67 68 (Justin won at the second play-off hole), Trevor Immelman (Rsa) 74 66 67 69, Robert Allenby (Aus) 71 71 69 65

277 Sergio Garcia (Spa) 68 72 71 66, Boo Weekley 65 75 69 68, Alex Cejka (Ger) 69 69 69 70, Padraig Harrington (Irl) 71 72 66 68

278 Gavin Coles (Aus) 73 64 70 71, Scott Verplank 71 72 67 68, Tom Pernice Jnr. 72 72 71 63

279 Vijay Singh (Fij) 67 71 70 71, Bob Heintz 73 70 68 68

280 Dean Wilson 69 68 71 72, Bob Estes 74 65 70 71, Tim Herron 74 67 69 70, Jason Dufner 69 68 72 71, Stephen Ames (Can) 69 71 68 72

281 Michael Letzig 70 68 72 71, Bill Haas 71 69 67 74, Dan Forsman 70 70 72 69, J.P. Hayes 70 71 69 71, Camilo Villegas (Col) 71 71 71 68, Tim Clark (Rsa) 72 69 64 76

282 Omar Uresti 70 69 71 72, Bart Bryant 69 76 67 70, Davis Love III 68 70 75 69, Heath Slocum 73 67 74 68, Tommy Armour III 66 71 73 72, Bob Tway 72 71 68 71, Brett Rumford (Aus) 69 73 70 70, Kenny Perry 71 71 69 71, Jeff Maggert 71 70 74 67, Glen Day 69 71 71 71, Stuart Appleby (Aus) 68 76 68 70

283 Jeff Overton 70 71 70 72, Brandt Snedeker 69 71 69 74

284 Richard S Johnson (Swe) 72 73 69 70, Vaughn Taylor 70 72 71 71, David Toms 72 72 71 69, Marc Turnesa 68 69 70 77, Craig Kanada 68 72 74 70

285 Michael Bradley 69 68 76 72, Fredrik Jacobson (Swe) 73 72 69 71, Jeff Gove 70 73 67 75, Scott Sterling 70 70 73 72, Rich Beem 71 72 70 72, Brandt Jobe 71 74 70 70, John Huston 71 69 75 70

286 Lucas Glover 71 71 74 70, Marco Dawson 71 71 72 72, Woody Austin 71 72 73 70, Ken Duke 72 72 73 69, Brenden Pappas (Rsa) 73 70 77 66, Bob May 75 69 70 72

287 Jin Park (Kor) 73 71 67 76, Jonathan Byrd 69 75 73 70

288 Jim McGovern 71 68 72 77, Jimmy Walker 70 74 72 72, Todd Demsey 73 72 72 71

289 Brian Gay 76 67 70 76, Garrett Willis 72 73 69 75, David Duval 70 75 72 72, Kevin Streelman 74 69 69 77

290 Charley Hoffman 69 75 71 75, Webb Simpson 71 72 75 72

291 Patrick Sheehan 73 70 72 76, Dicky Pride 75 70 75 71, Stephen Leaney (Aus) 70 74 73 74

292 Brad Elder 69 76 73 74, Eric Axley 70 71 78 73, Harrison Frazar 72 70 74 76, Troy Matteson 74 70 71 77

293 Billy Andrade 76 68 73 76