It was the fifth time McNulty has won the South African Masters title and the sixth time as a professional that he has tasted victory on the Wild Coast course.
In a final round that saw the leaderboard fluctuate from the first hole, the 47-year-old held off South Africans Retief Goosen and Des Terblanche who both finished a stroke back on 275, five-under par.
McNulty started the final round in the worst fashion with a double-bogey at the par-four first and a bogey on the par-four second, dropping from nine-under to six-under in dramatic fashion.
'On the first hole I hit an eight-iron over the back from 158 yards,' McNulty said. 'I was in bushes behind the hole and I had nowhere to go so I hacked it out sideways and then chipped it up to six feet and missed the putt.
'On the second I hit a sand wedge onto the green, which just trickled down a little way and I three-putted and suddenly I was under pressure.
'It was a frustrating day because most of my shots were good but nothing was happening out there. It's all about emotions and I couldn't control them after the start that I had.
'I was very tense the whole day, which came about because of the way I started. I suppose you only need to win by one shot, but the only sad thing is that I don't like to shoot over par to win a tournament.'
It might have been a frustrating day for the winner, but it was his 49th career title and once the reality of this achievement - and the fact that he is second only to Gary Player in Masters titles victories - sets in, McNulty will forget about the final day frustrations and look back with pride.
On a day when few players could put a meaningful run together, McNulty trailed Des Terblanche by a three-strokes after five holes before somehow composing himself enough to grind out a victory that looked a certainty after the third round.
Bogies on 11 and 14 for Terblanche coming down the stretch enabled McNulty to reclaim the ascendancy, which nearly ended on the 18th when an errant tee-shot found the fairway bunker.
'I hit my drive too softly and landed in the bunker which I really should have cleared,' McNulty said. 'I was lucky though, because a few inches behind my ball was a big hole in the sand from poor raking. If I had landed in that it would have been impossible to make the green.'
History will record that he put the ball safely on the green and two-putted to take the title, more to feelings of relief than elation.