Danny Willett set his sights on a place in the Olympics and Ryder Cup after holding his nerve to win the Dubai Desert Classic and take a massive step towards a place in the world's top 10.
Sullivan had also birdied the last in the group ahead to temporarily join Willett at the top of the leaderboard, before Cabrera-Bello narrowly missed a long eagle attempt on 18 and tapped in for birdie to also finish 18 under.
Spain's Alvaro Quiros and Korea's Byeong Hun An shared fourth place on 16 under after matching rounds of 65, with defending champion Rory McIlroy another shot back alongside Henrik Stenson after also closing with a 65.
"I'm just ecstatic," said Willett, who revealed his celebrations would be somewhat curtailed by a 3am flight home to be with his pregnant wife Nicole. "You can't buy that feeling, coming down the back nine, the last three holes, in contention in a golf tournament. You can't pay for that experience, you've got to earn it.
"With all the permutations that were going on as we were coming down the last, with Sully making birdie ahead of us and then Rafa on the green in two, it's very nice to know that I can dig deep and produce what I can when it is needed the most.
"You'd love to win by five or six every time, but when you win in that fashion it does feel that little bit extra special. It means when the pressure is on I can produce the goods."
Willett's fourth European Tour title moves him from 20th in the world rankings to a provisional career-high of 12th, as well as elevating the 28-year-old to third in the Ryder Cup standings and cementing his place alongside Justin Rose in qualifying for the British Olympic team.
"You try not to think about it when you're on the golf course but they are two massive goals of mine," Willett added. "I'll do the same thing I've been doing the last couple of years, it's just day by day, week by week, and hopefully come August we'll be in Rio and come September we'll be in Hazeltine."
After losing his overnight lead following a bogey on the second, Willett twice surged three shots clear before a three-putt bogey on the 14th, coupled with Sullivan's birdie on the 15th, set up a tense finish.
Sullivan then saved par on the 16th after a wild drive in the trees and birdied the last to share the lead, but Willett left himself a slightly longer putt on almost exactly the same line as his former Walker Cup team-mate and calmly holed for his fourth European Tour title.
"Fair play to Danny, that was a tough putt," Sullivan said after a closing 68. "I didn't feel like I put him under enough pressure through the midpoint of the round. I had a lot of chances and didn't take them.
"The putts towards the end kept me in it, par saves, and when you hole that putt on the last, you feel you've given yourself a sneaky chance. But Dan is a quality player and you expect him to step up, and he did." McIlroy was left to rue some poor passages of play as he failed to join Ernie Els in winning a third title at Emirates Golf Club, the world number two having said at the start of the week he would be disappointed with anything less than a win.
"It's sort of a week of what could have been," said McIlroy, who finished joint third in Abu Dhabi a fortnight ago. "There was a lot of really good golf in there. I played a lot of great shots and made a lot of birdies, but just made a few too many mistakes as well. I played the combined front nine in five over on Friday and Saturday and if I had not of done that, things could have been different.
"It's been nice to shake the rust off these last couple of weeks. It gives me a good understanding of what I need to do going into the next few weeks.
"I'll have a week at home, which will be nice in my own bed, a week to work on my game a little bit and get ready for the Northern Trust Open in LA the week after next. Then I think I'm playing five events in a six-week stretch, so it's a busy run of golf coming up, but I'm looking forward to it."