Ireland centre Gordon D’Arcy, fresh from his hamstring problems, had his first outing in four weeks – he played an hour and sparked the Leinster backline into action late in the first half, but was able to do little as a 66th-minute Jason Spice try and the boot of both Shaun Connor and his replacement the talented Wales Under-21 player Matthew Jones helped the Welshmen to only their third win in nine trips to Ireland.
The home side endured a frustrating opening period as the elusive Spice had a fifth-minute try ruled out for having a foot in touch. Fly-half Connor kicked just one of three penalty shots and his seventh-minute goal from 40 metres was the game’s only score until first-half injury-time when Christian Warner’s effort left Leinster 5-3 up at the break.
In the second half a Guy Easterby hack-through created havoc in the Welsh defence and with Kieran Lewis drawing his man in, centre Warner turned on the gas and outpaced Richard Pugh for the corner for his third try in two matches.
Holwell missed the conversion wide and was made to pay after 57 minutes as Connor – who had missed his fourth attempt early in the second half – made amends for a 6-5 lead.
The Ospreys were beginning to dominate and a blindside dart nine minutes later saw the Leinster defence all over the place. Dave Tiueti and captain Barry Williams were picking-and-driving to good effect, and Spice got the touchdown from a close-in ruck.
Matthew Jones tagged on the conversion and added an easy 73rd-minute penalty, with substitute prop Emmett Byrne banished to the bin for preventing a quick release. With Byrne in the bin Leinster pilled on the pressure late on and got in for their second try through captain Shane Jennings. A searing Warner break allowed Jennings set up a grandstand finish but Holwell’s touchline conversion mattered little in the end as the Ospreys held on for their 13th and most crucial win of the campaign.