Leishman, 30, posted his fourth top-10 finish for the year by tying for eighth at the Quicken Loans National at Congressional Country Club in Maryland.

A final-round 74 yesterday morning meant he finished the tournament at one-under, three shots behind Englishman Justin Rose and American Shawn Stefani.

Rose beat Stefani on the first play-off hole to claim his sixth US PGA Tour triumph. They each shot final rounds of 70, among just six who broke par for the day.

Leishman, speaking minutes before boarding a plane, lamented letting slip a major chance to add to his sole tour victory, the Travelers Championship in 2012.

He started the final round two shots off the pace and looked good for victory when he birdied the first hole, having approached to within a metre of the pin.

But five bogies later — and only one more birdie — consigned him to a share of eighth. His first three rounds were 70, 66 and 73.

“I’m definitely getting closer,” he said. “It’s a good result today but I’m still pretty disappointed. I had a good chance to win and I wasn’t able to hole the putts.”

Leishman said he gained confidence in knowing he produced below-par golf for the final two rounds, yet finished just three shots short of victory.

“I wasn’t far away. I left a lot of shots out there and I was only three away from winning. That itself gives me confidence,” he said.

“I’m just really disappointed at the moment but I’m not giving up or anything. I know I’m really close.

“Hopefully I can do the same things next week and finish off a little bit better.

“It’s the finishing touches really. It’s not like the engine is broken, it’s a few scratches of paint.”

Leishman, the youngest winner of a Warrnambool Golf Club championship at 13, is in the midst of his best year on the tour since turning professional in 2005.

His four top-10 finishes include two in the past six weeks — he was third at the Byron Nelson Championship in May. The other two came in a fortnight in January.

He has amassed $US1.43 million in prizemoney with 12 events to go, including two majors — the British Open in July and the PGA Championship in August.

But he needs to add consistency to his game to turn encouraging performances into tour victories. His efforts to close out tournaments this year have undermined his early efforts.

“That’s exactly what’s happening, which I know. At least I’m getting myself into those positions and giving myself chances to win,” he said.

“The more chances I give myself, the better I’ll get at it. Hopefully I’ll work out what’s going wrong.

“I’m hitting the ball good enough, I’m just not quite putting it together on the weekends. The greens speed up, there’s a little bit more pressure,” he said.

“There are a few different things happening. I’m not exactly sure what’s going wrong but hopefully I can work it out, fix it up and win another tournament.”

The next US PGA Tour event is the Greenbrier Classic at the Old White TPC in West Virginia, which starts on Thursday.

afawkes@fairfaxmedia.com.au