Hobbling off after nine minutes' play was no way for David Humphreys to end his rugby-playing days, but the 9,672-strong crowd had to make do with an all too short glimpse of the Ballymena man back in the number 10 jersey.

The 36-year-old's final season has been ruined by an Achilles tendon injury but with coach Matt Williams' persuasion and a good deal of work between himself and the Ulster medical staff, Humphreys earned himself a starting spot in the province's final game of the season.

Unfortunately, as is often the case in rugby, things never work out as they are plan and with the injury resurfacing, Humphreys had to call it a day just as the game got going.

The former Ireland international got a huge ovation from the Ravenhill faithful as he made his way to the sideline, leaving the out-half duties to Paddy Wallace who, along with Niall O'Connor, will have another rival for the number 10 jersey next season in Humphreys' younger brother Ian.

Continuing where they had left off against Connacht seven days ago, Cardiff started brightly despite missing a number of players due to Wales call-ups and injuries.

Young wingers Roger Davies and Leigh Halfpenny both made their debuts for the Blues, who were over for their first try after only four minutes.

Ulster were hoping to give winning send-offs to Humphreys, Justin Harrison, Tommy Bowe, Neil Best, Roger Wilson and Mark Bartholomeusz but the Blues had not read the script.

All the early pressure came from the Welsh region and with Wilson losing possession off a scrum close to the Ulster try line, Cardiff seized their opportunity with flanker Maama Molitika barging over under the posts through some poor tackles.

Debutant Halfpenny knocked over the conversion, helping to settle his nerves, but after Humphreys' departure the hosts got themselves up and running.

With his first touch, replacement Wallace put Andrew Trimble haring through a gap and he combined with his Ireland colleague Bowe.

The Ospreys-bound Bowe was tackled short of the try line by Halfpenny but the Ulster number 14 wriggled out of the tackle to get over for an unconverted score.

But Cardiff continued to look the more dangerous side and only for some tigerish defending from the hosts, David Young's men would have added to their early try.

As it was, Ulster managed to nip ahead before half-time. During a sustained period of pressure in injury-time, Wallace was again the instigator for an Ulster try.

The swiftness of one such attack caught the Blues defence napping as Wallace put Simon Danielli into space and the Scotland winger powered past three tacklers to touch down.

Wallace's conversion gave Ulster a 12-7 interval lead but the Blues regained control of the game on the restart with two tries in the space of four minutes.

Roger Davies marked his debut with a 44th-minute try as he showed good pace to latch onto the ball and score after a kick-and-chase rumble forward.

Halfpenny converted to take the Blues into the lead and they moved further ahead when the Ulster defence was again caught napping as they allowed replacement lock James Down an easy run-in to the line.

Williams unloaded his bench, sending on forward trio Neil Best, Justin Fitzpatrick and Matt McCullough and they helped make an impact up front.

Just as Ulster had done in the first half, Cardiff coughed up scrum possession near their line and Wallace nipped over for a well-taken 65th-minute try.

The Ireland out-half could not tag on the conversion though and Ulster sensed it was not going to be their night when they failed to follow up with a try after McCullough had blocked down a Nicky Robinson clearance kick.

It was left to the in-form Molitika to dash Ulster's hopes as he snuck over for his second try of the contest, which Halfpenny converted.

The result, Ulster's second successive home defeat, left them second-from-bottom in the final league table, while for the second season in a row the Blues are runners-up in the competition.

Young and his players can be pleased though with how they played in the title run-in as this was their fifth straight win - a feat the region had not achieved since the 2005/06 league season.