He got what he needed from fellow Australian Stuart Appleby.
Scott held off Appleby with a 6-under 66 on Sunday, saving par with a 50-foot putt on the 72nd hole after hitting his tee shot into the water.
Scott finished at 17 under, three strokes ahead of Appleby, the defending champion, and third-round leader Bubba Watson.
Scott said before the tournament that he was rusty after taking a month off earlier this year. He tied for 61st at Doral and was pleasantly surprised how well his game held up under pressure this week heading into the Masters.
'It was good for me to play in the heat of the battle again,' Scott said. 'Just to know how to control your nerves will be good for me.'
Playing together, Scott led Appleby by one stroke as they stood on the 18th tee, but Scott pulled his tee shot into the pond that lines the left side of the 488-yard hole, the course's most difficult.
Scott immediately had a flashback to the 2004 Players Championship, when he had a two-shot lead on the final day and pulled a 6-iron into the water on the 72nd hole.
'I don't know. Water on the left,' Scott said. 'It's not ideal for me, obviously.'
He salvaged a winning bogey at Sawgrass and got away with it again Sunday.
Appleby drove into the fairway bunker, then immediately gave Scott a reprieve by hitting his approach into the water near the green.
'I knew what I had to do,' Appleby said. 'It's just a matter of you've got to do it. And I didn't get to do it.'
Scott took his drop, hit his approach safely away from the water, then holed the par-saving putt. He pumped his fist, Tiger Woods-style, after the ball disappeared and the crowd roared.
'It was relief, along with elation,' said Scott, who earned his first win since last year's Tour Championship. 'I was pretty happy for it to be all over with, because it was looking a bit messy.'
Appleby took a double bogey to finish with a 69. But it was easily his best finish of the year and filled him with confidence heading to Augusta.
'I like the way I hit the ball,' he said. 'I want to get there (to Augusta) and get set for that. I'm ready to go.'
Watson, searching for his first win, birdied the last hole for a 72.
Scott became the sixth Australian to win the Houston Open, joining Appleby, Bruce Devlin, Bruce Crampton, David Graham and Robert Allenby. Appleby and Crampton have won it twice and the eight victories by Australians are the most in any U.S. tour event. Only the British Open (9) has had more champions from Down Under.
Appleby joked that it eased the sting of losing to know that another Aussie won.
'Marginally,' Appleby said.
The 26-year-old Scott spent four weeks in Europe before returning at Doral. He shot a final-round 80 -- including a 10 on one hole -- and wasn't optimistic before the Houston Open started.
But his swing held up all week and his putting improved with each round, even when his nerves started to fray.
'I really needed to be in contention this week and take something out of it,' Scott said. 'I can feed off that for next week now.'
Appleby and Scott started the day three shots behind Watson, but caught him with birdies on three of their first five holes. The Aussies matched each other shot for shot from there until Appleby bogeyed the par-3 14th and lost the lead for good.
Scott hit two mammoth 3-woods to reach the 608-yard 15th hole and he two-putted to move to 17 under. Appleby bogeyed the 16th, then birdied the 17th to set up the tense finish.
'It's funny what happens coming down the stretch,' Scott said. 'We were solid all day and all of a sudden, you know, a couple of funny shots happened.'
Players were allowed to lift, clean and place their balls in the fairway for the second straight day after a morning thunderstorm dumped a half-inch of rain.
Storms Saturday morning postponed the start of the third round for six hours and Watson was one of 27 players who came back Sunday morning to finish.
Watson bogeyed two of the three holes he played as the sun came up, but still shot an 8-under 64, which tied the course record set on Saturday by Johnson Wagner.
Wagner, a 27-year-old tour rookie, started the final round in a five-way tie at 11 under, along with Scott, Appleby, Houston resident Jeff Maggert and Paul Stankowski.
Robert Garrigus birdied four of the last five holes, capped by a 60-foot putt on the 18th hole, to shoot 65 and finish 12 under. ... Tommy Armour III, who got into the tournament through a local qualifier last Monday, shot a final-round 66 and finished 13 under. The 47-year-old Armour earned his biggest paycheck ($264,000) since tying for second at the 2004 Chrysler Championship. ... David Toms, who helped design the course with Rees Jones, finished 6 under.
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