It was the fourth win of the season for the 24-year-old European Tour rookie and lifted him into third place in this year's Race to Dubai.
He is now only 730,000 euros behind leader Rory McIlroy and as he accepted his 617,000 euros winners cheque Grace admitted he has was now focused on the beating the world number to the top honour in European golf.
"I am all for catching Rory," Grace said after shooting a closing 70. "Someone mentioned the possibility to me a couple of days ago and then I said let's get this week over with first and I have done that.
"And now I am in third place, first place is definitely in my sights. With a lot of big money events coming up 800,000 is not a lot to make up."
Furthermore Grace will be playing more events through the rest of the season than the young Ulsterman.
In the week ahead McIlroy will be in Turkey with seven of the world's other top golfers, including Tiger Woods, chasing a $1.5 million first prize in an exhibition tournament.
Grace will be at the European Tour's Portugal Masters where pocketing the 600,000 euro prize would make a huge dent in McIlroy's lead.
Although Grace took a four-shot lead into the fourth round his victory which has lifted him from 265th in the world at the start of the year into the top 40, was not a straightforward procession.
When he dropped shots at the seventh and 11th holes around the Old Course he was caught at the top of the leaderboard by the Dane Thorbjorn Olesen who won this year's Sicilian Open.
After three-putting the 11th green Grace said he turned to his caddie Zach Razego to help him read the lines of his putts and a run of three birdies from the 12th put him back on the victory trail.
Olesen shot 68 to finish second with the Swedish pair of Alexander Noren and Joel Sjoholm in third and fourth places.
Scot Stephen Gallacher was at one stage poised to challenge for a podium finish. At the 16th hole he was lying fourth on the leaderboard but incurred a two-shot penalty for playing the wrong ball.
Instead of hitting his own ball he played one belonging to Yorkshireman Streve Halsall who was the amateur playing partner of the Englishman Graeme Storm playing in the same group.
Gallacher eventually had a quadruple eight at the hole and had to settle for being part of a seven-way tie for fifth place.
- Rory McIlroy