A two-and-a-half hour delay for dangerous weather conditions on Sunday forced a Monday finish at Donnafugata Golf Resort & SPA, with the leading pair resuming with just one shot separating them and six holes to play.
Wall twice wiped out the deficit, only to find water at the penultimate hole and run up a double bogey as 36 year old Jacquelin walked away with the €166,660 first prize.
Jacquelin closed with a three under par round of 68 for a 12 under par total, finishing one shot clear of Wall after his playing partner birdied the last.
“It feels great – as you would expect it to feel,” said Jacquelin, who climbs back into the world’s top 100 with his victory. “But it was not easy – Anthony made a couple of birdies and put the pressure on me right from the start.
“I actually felt a little bit tired this morning and my ball-striking wasn’t as good as it has been but I suppose with a 5am wake-up call then I was expecting that.
“But I stayed patient and made a good birdie on the 14th which was perfect and then he made a mistake on 17 and that was it, although I had to make a good four at the last.
“It was a good fight between the two of us and I think that helped us to play the way we did because we were always close and playing together made it a good fight. I enjoyed it and there can only be one winner – I am glad it was me.”
Teeing off at 7am, Wall was immediately level when he birdied the par three 13th.
But - as he had when Wall birdied the first hole of the final round to draw level - Jacquelin responded with a gain of his own at the very next hole.
Wall - whose only previous European Tour title was 11 years ago - looked to have forced a play-off when he picked up another shot at the par five 16th.
But he failed to capitalise on his momentum, and his six at the 421 yard 17th proved costly, his gain at the last only enough to reduce the arrears.
“I have to say that I am disappointed,” admitted Wall. “We pushed each other all the way and you have to say that it was a fitting way to end the tournament and good to watch.
“I thought I had hit the green on the 17th and it was just a yard short and pitched on top of the slope and pitched straight left in the water.
“It was tough because if it had landed anywhere else it would have just come to rest on the edge of the green so that was a tough one to take.
“I came and birdied, then he hit back and it was good to watch I’d imagine. Raph and I are decent friends and have a lot of respect for each other because we have known each other a long time and came out on Tour the same year so I think we both enjoyed the battle.
“I often restart very well and I did it again today which was pleasing but at the end of the day it came down to one bad swing, or half a bad swing I should say. It was a good test all week and I just failed ever so slightly which is a real shame for me.
“At least I asked the question at the last and to be fair to him he has responded and did what he had to do on the hardest hole on the course. But I am pleased with my game and the mind is in good shape generally so I am reasonably happy looking forward. I feel there are wins in me and I take a lot of positives from the week.”
Spaniard José Manuel Lara - who was only two behind Jacquelin with three to play overnight - also had a double bogey, his at the last, as he tied with Swede Joel Sjöholm for third on seven under.