Marcel Siem closed with a 2-under 70 on Sunday to win the Trophee Hassan II in wire-to-wire fashion.
Siem finished his third European Tour title at 17-under-par 271. His 4-shot lead to start the round was gone by the sixth. However, birdies at seven and 11, coupled with struggles of those chasing him, pushed Siem's lead to five with seven holes to go.
The German played the final seven holes in even-par to seal the win.
"I'm super happy. I'm pretty proud I stayed calm," admitted Siem.
Mikko Ilonen, playing a group ahead of Siem, was 4-under through seven holes to earn a share of the lead. However, he played the back nine in 1-over par en route to a closing 69. He shared second place at minus-14 with David Horsey, who also shot 3-under 69 on Sunday.
Pablo Larrazabal managed a 1-under 71 at Golf du Palais Royal to end alone in fourth place at 12-under-par 276.
Siem stumbled to a bogey at the second, but bounced back with a 2-putt birdie at the fifth to get back to 15-under.
Meanwhile, Ilonen poured in three straight birdies from the second to get to 14-under. He joined Siem in the lead as he birdied the seventh for the third straight day. Ilonen dropped three strokes in the first three holes around the turn, and never got back into it.
The 32-year-old Siem regained the lead with a 5-foot birdie putt at the seventh. Around the turn, he pushed his lead to five strokes with an 18-foot birdie effort at the par-4 11th.
Siem 2-putted for birdie from the fringe on No. 15 to push his lead back to five. Siem bogeyed the last to trim his winning margin to three.
"On 18, I just tried to rip one over the forest because yesterday and the day before I faded them too much, but it's alright. Bogey was okay on 18," Siem stated. "I'm really happy. In between was a lot of pressure. Mikko had a great start again and I thought it was going to be a little easier, but I'm happy I came back."
Siem had a chance to gain an invitation to The Masters in two weeks with the win, but Henrik Stenson finished in a tie for second place at the PGA Tour's Houston Open later Sunday to move inside the top 50 in the world rankings and push Siem out.
NOTES: Siem collected 250,000 for the victory ... He had played 226 European Tour events between his first and second wins, but just 18 between his second and third titles ... Siem was the fourth wire-to-wire winner this year on the European Tour ... The tour is off for two weeks before returning with the Reale Seguros Open de Espana, where Francesco Molinari won last year.