Dan Biggar kicked six penalties to steer the Ospreys back from the brink of defeat as they overturned a 13 point deficit to beat Ulster 23-22 at the Liberty Stadium.
The axed Welsh outside half guided the Magners League champions to a much needed victory that keeps them in touch with the top four teams on a weekend when two of them slipped up away from home.
The Scarlets were pipped in Connacht and runaway leaders Munster were overturned in Treviso, so the Ospreys needed to make the most of the weekend by closing the gap on the front runners for the four Play-Offs places on the road to the second Magners League Grand Final on Saturday, 28 May.
The four points looked a long way off after Ian Humphreys had given Ulster a 13-0 lead with two penalties and then a penalty try which he also converted. In much the same way as they had blown away Cardiff Blues on their last visit to Wales, when they ran out 37-15 winners, Ulster scored at almost a point a minute in the opening quarter to create what looked like being a winning platform.
But after that bright opening the Ospreys scrum began to turn the screw and the penalties flowed as the Ospreys finally got their act together.
That allowed Biggar to prove he can still hit the mark with his goalkicking as he landed six out of eight attempts to punish the visitors. One of his penalties was a monster from 55 metres on the stroke of half-time that gave the home side the lead for the first time at 14-13.
As well as Biggar's three penalties the Ospreys also conjured up a corner try for ex-All Black flanker Marty Holah which owed much to the skill and vision of Ashley Beck, who threw a long, cut out pass to create the opening.
Two silly home indiscretions at the start of the second half allowed Pienaar, who took over at outside half from Humphreys when he left the field with a shoulder problem after 31 minutes, to show off his considerable goalkicking skills and Ulster suddenly found themselves five points clear.
But Biggar replied with three more penalties, two for scrum offences, and not even a third strike from Pienaar six minutes from time could claw back the deficit.
Scorers:Ospreys: Try: M Holah; Pens: D Biggar 6. Ulster: Penalty Try; Con: I Humphreys; Pens: R Pienaar 3, I Humphreys 2
With Liam Williams forced out of the World Cup through injury, lock Luke Charteris and Skills Coach Neil Jenkins say they have to put yesterday's defeat behind them as Wales now look ahead to another physical encounter against South Africa in the quarter-finals of the Rugby World Cup.
WRU Consultant Head of Physical Performance Paul Stridgeon praises the Physical Performance department for their work and dedication as he addresses the media ahead of Wales' Pool A clash against Australia
Twelve young people have been selected to follow a one year WRU Coach Core apprenticeship programme. Coach Core was set up by the Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry as part of the Olympics legacy in 2012 and the Duke of Cambridge was on hand to meet the apprentices on their first day in the job. The programme has been funded by the Hunter Foundation.
The WRU has launched a campaign to create a long term legacy for Welsh club rugby by highlighting the advantages of volunteering. Rhian Edwards, a volunteer at Seven Sisters, has enjoyed many benefits of her volunteering at a grassroots rugby club including being part of the Rugby World Cup volunteer workforce after being nominated by the WRU - and the WRU is asking for more people to develop their 'Welsh rugby roots'.