Spain's Alejandro Cañizares was closing in on a first European Tour title since 2006 in the Trophée Hassan II as his nearest challengers started to fall away in Morocco.
Cañizares took a one shot lead over England's Seve Benson into the third round at Golf du Palais Royal, but had extended that to six shots despite only being two under par for 13 holes.
A bogey on the fourth and birdie on the fifth took Cañizares to the turn in 36 and two ahead of Benson, who had bogeyed the first and then recorded eight straight pars.
Cañizares then two-putted from just off the green on the par five tenth to record his second birdie of the day, while Benson ran up a bogey six after his approach plugged in some mud on the bank of a water hazard to the right of the green.
Benson hit back straight away with a birdie on the 11th, but then took an even more costly six on the par three 12th after finding a greenside bunker off the tee.
The 27 year old overhit his recovery shot and watched as it trickled agonisingly into the water on the other side of the green, and after taking a penalty drop in the sand needed three more to get down.
Cañizares birdied the 13th to improve to 16 under par, six ahead of Dutchman Robert-Jan Derksen who was five under par for his round with one hole to play.
Benson was a shot behind on nine under, with former European Tour Number One Robert Karlsson, his fellow Swede Magnus A Carlsson, English trio David Horsey, Paul Waring and Richard Bland and India’s Shiv Kapur another stroke back.