The former South Africa scrum-half made a major contribution to three of his side's five tries from Stuart McCloskey, Chris Henry, Charles Piutau, Darren Cave and Kyle McCall and converted all five of them himself.

Ruan Pienaar was the Guinness Man of The Match pictured here with @gembell87 representing Guinness pic.twitter.com/Kj2imB7sA8

— Ulster Rugby (@UlsterRugby) December 3, 2016

The Blues' miserable run of form continued with a fourth loss in five games at the Arms Park with their tries coming from Kristian Dacey, Alex Cuthert and Willis Halaholo. Steve Shingler kicked a penalty and Nicky Robinson added two conversions.

Sam Warburton was a late withdrawal with a sickness bug but Blues overcame this setback to take a fourth-minute lead through Shingler's early penalty.

Cardiff continued to dominate the opening quarter with centres Halaholo and Ray Lee-Lo a constant threat to the Ulster defence but the home side failed to take advantage on the scoreboard.

Poor handling and a lack of ball retention was a feature of a stop-start first 20 minutes as both sides struggled to bring any continuity to their play.

However after their slow start, Ulster rapidly improved and Pienaar brought the game to life with a clean break from a scrum on the home 22. Cardiff were then penalised with Blaine Scully yellow-carded before Piutau capitalised by scoring the opening try after 24 minutes.

Four minutes later, McCloskey drifted past some weak defence from Blues to score Ulster's second and with Pienaar converting both, the visitors held a healthy 14-3 lead.

Scully returned from the sin-bin but Pienaar continued to have a major influence on the game and when the scrum-half charged down a clearance from Lloyd Williams, McCall was on hand to cross.

Pienaar's conversion put Ulster almost out of sight but Dacey gave the hosts renewed hope by scoring from close range although the Blues still trailed 21-8 at the interval.

Two minutes after the restart, Ulster suffered a blow when Iain Henderson was yellow-carded for a high tackle on Cuthbert but despite some sustained pressure Blues failed to add to their score in the flanker's absence.

Cardiff brought on Matthew Morgan in place of Tom James and replaced both props in the hope of reversing their fortunes but it did not pay immediate dividends as the third quarter remained scoreless.

Ulster lost another player to the sin-bin when Luke Marshall was penalised for a deliberate offside but despite the excellent efforts of Dacey and Halaholo, the hosts continued to play poorly and squandered chances.

Robinson came on for Blues after a seven-year absence from the region but there was to be no happy return as Henry finished off a flowing Ulster move to score their bonus-point try.

Halaholo and Cuthbert scored late tries for Blues but it mattered little as a Robinson kick was charged down by Cave to seal victory for the Irish province.