Owned by Sheikh Khaled BIN ZAYED AL NAHYAN and skippered by Christophe VANEK (FRA), the 36ft series leader suffered her first defeat of the weekend in the day's opening race but then bounced back immediately with victory in the penultimate race.
It was another reminder that it will take a major change in fortunes to prevent Horizon from becoming the first winner of the Maktoum Sailing Trophy, with just two rounds remaining this month.
The opening race saw four boats reach the first mark ahead of Horizon, and VANEK finally had to settle for fourth spot on handicap as Serdal Dubai, owned by Sheikh Rashid BIN KHALIFA AL MAKTOUM and skippered by Mark FEILBERG (AUS), shared victory with David WORRALL's (UAE) Sharazad after both recorded identical times.
Switch Blade skippered by David ROSTANT, Xclusive skippered by Yousef BIN LAHEJAND Patrick CAHILL's Southern Cross completed the top six.
In Class 2, runaway series leader John ROSE in Insatiable won from Time Out skippered by David MADDEN and John FORDS's Irene.
If the opening race had given hope to VANEK's two closest challengers, WORRALL and FEILBERG, the Frenchman provided an emphatic response with victory in the day's second race. On this occasion ROSTANT took Switch Blade to second place ahead of Serdal Dubai, Shaharazad, Xclusive and Southern Cross.
With lights winds scattering the fleet as the boats went in pursuit of some energy, the husband and wife combination of Karen and Glywn ROWLANDS were next home in Twister from Alan SKENNERTON in Shockwave Aquamarine.
In Class 2 ROSE had to be content with second place behind Time Out as MADDEN held on to his overall fifth round lead, with Irene taking third position.