Marcus Fraser leads Olympic golf by one, Henrik Stenson and Justin Rose in hunt

Marcus Fraser had his Olympic golf lead trimmed to just one shot as Henrik Stenson and Justin Rose remained in contention at the halfway stage in Rio.

Fraser came back to the field with two dropped shots on the back nine, but he birdied the last hole to card a two-under 69 and reclaim the outright lead on 10 under - one ahead of Thomas Pieters.

Stenson, who made an outrageous par save at the third after pulling his tee shot into water, is two off the pace following an erratic 68, while Rose compiled a steady 69 to close on six under par.

Fraser, who only made it to Rio when the likes of Jason Day, Adam Scott and Marc Leishman withdrew, continued to take advantage of his call-up as he cruised to 10 under with birdies at the third and fifth, where he almost holed his wedge approach for an eagle.

The Australian picked up another shot at 11 after a superb 215-yard second to five feet, but he blotted his card for the second time in the tournament after misjudging his approach to the next, and a poor pitch at the driveable par-four 16th rolled back off the green and cost him another bogey.

But he atoned with a delightful chip to 18 inches to set up a closing birdie at the last, which took him back in front of Pieters, who birdied the first three holes and responded to bogeys at 11 and 14 with another three consecutive birdies which capped an excellent 66.

Stenson birdied the opening two holes but looked certain to give at least one shot back with his erratic tee shot at the third, but he hammered his third from short of the water 243 yards onto the front edge of the green before holing a remarkable par putt from over 100 feet.

But the Open champion did bogey the par-three next after dumping his tee-shot into sand, but he drained a 25-foot putt for birdie at the short eighth before three-putting at the 14th green.

The Swede birdied the next two holes, but his problems with the par-threes continued with another blemish at the 17th, although he rattled in a confident six-foot putt for a closing birdie to get back to eight under.

Rose birdied the fifth and sixth but struggled to make much happen thereafter, and he was content to grind out the pars until dropping his only shot of the day after bunkering his approach to the 15th.

The Team GB star, who made what is believed to be Olympic golf's first ever hole in one in the first round, missed a five-foot birdie chance at 16, but he holed from double that distance on the 17th although he was unable to close with a four at the long last.

Rose shares fourth with Gregory Bourdy (69), while likely Ryder Cup rookie Rafael Cabrera-Bello is one further adrift despite running up a triple-bogey seven at the third after emulating Stenson's drive into the lake.

The Spaniard started to repair the damage with a birdie at 10 and, like Pieters, managed to birdie each of the closing three holes to salvage a hard-fought 70.

New Zealand's Danny Lee went one better than Pieters and Cabrera-Bello, carding four consecutive birdies to finish off a best-of-the-day 65 which lifted him 28 places up the leaderboard to five under.

Ireland's Seamus Power stormed into the top 10 after an excellent 67 which featured four birdies over the a flawless first 11 holes, and he also pitched in from 25 yards for eagle at the 16th in between a pair of dropped shots.

Power's vastly more experienced team-mate Padraig Harrington dropped three shots in four holes after the turn before birdies at 17 and 18 rescued a 71 that kept him on one under alongside Sergio Garcia, who mixed three birdies with four bogeys in a disappointing 72.

Masters champion Danny Willett was another player to birdie the final three holes as he also closed on one under along with two-time Augusta winner Bubba Watson, but Rickie Fowler remained on four over after a 71 littered with four bogeys, including three in a row from the 11th.