MADRID, Spain -- South Africa's Charl Schwartzel shot a 5-under 66 Sunday to win the Madrid Masters by three strokes over Ricardo Gonzalez of Argentina.

Schwartzel, who had led since the halfway point, overcame sickness and shoulder and back pain to finish at 19-under 265 for the tournament at the Club de Campo golf course.

The 24-year-old got two early birdies to pad his overnight lead of one shot, and another three after the turn.

Schwartzel's previous European Tour victory came in last year's Spanish Open.

"I woke up this morning and felt a lot better than I have been feeling," he said. "I thought I ground it out nicely all week. I just managed to keep it going today."

Gonzalez, who shot a 62 on Saturday, posted a final-round score of 68 and finished at 16 under.

Pablo Larrazabal (67) placed third at 15 under, one better than fellow Spaniard Alvaro Quiros (64) and England's Robert Rock (64).

The South African took a one-shot lead into the final round following scores of 69, 64 and 66 and he was in imperious form again, racking up two birdies on the front nine and three more on the way back.

Gonzalez, who came from nowhere with his 9-under-par 62 in the third round, threatened in patches to overthrow the South African atop the leaderboard, as did Rock, who launched an early assault on the way to a stunning 7-under-par 64.

Larrazabal had two early birdies, but he lacked the same spark that ignited his 9-under 62 on Saturday and his 67 meant he finished third on 15 under.

Ultimately the classy Schwartzel was too strong, despite admitting earlier in the tournament he had been struggling with injury and illness.

The par-5 seventh hole was a turning point in the battle between Schwartzel and Gonzalez.

The former hit his second shot way right of the green, but produced a well controlled chip out of the trees to within three feet and sank the putt for birdie. Gonzalez, however, had a five-footer for birdie which slid wide, and he had to settle for a seventh successive par, allowing Schwartzel to creep three shots ahead.

Rock, four groups in front, increased the pressure, his birdies coming in clusters at Nos. 2, 3 and 4, 7, 8 and 9, and then 12, 13, and 14, but Schwartzel turned the screw midway through the back nine.

A sublime approach shot at 13 left him with a six-foot putt for birdie which he holed, and he moved to 18 under on the next hole with some equally impressive short play. Another birdie followed on the par-3 17th after he put his tee shot within six feet, all but clinching the title.

Schwartzel admitted he was glad he took his father's advice on Friday to not withdraw from the competition. He had considered pulling out because of a shoulder problem and a virus, but persevered following a telephone conversation with his father, George.

"I spoke to my dad and he told me to tee off and see how I feel," he said. "I haven't felt great. I had a shoulder problem and some sort of flu bug which has been going around -- several other players on the Tour have had it.

"I've been waking up in the mornings feeling achy and sore and not having any energy, but this morning I actually felt a bit better and I'm glad I kept my swing going the way it has been the past three days."

Rock was delighted with his final position and a performance which comprised scores of 70, 65, 71 and 64.

"I played great the front nine," he said. "I made a real mistake on the 10th. It was a wrong decision from the tee. But I'm absolutely happy with how I've done. My goal for the week was to finish in the top 10 and it's great.

"I have to check if I've secured my card," he added. "Next week is also important but if I play half decent, I'll get it done."

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