Saracens will face Munster in the Heineken Cup semi finals after masterminding a stunning 19-10 triumph over glamour Welsh outfit Opsreys at a rocking Vicarage Road this afternoon.

A try for replacement Francisco Leonelli and 14 points from masterful fly-half Glen Jackson booked the Men in Black an April 27 trip to Coventry's Ricoh Arena where Sarries boss Alan Gaffney's former club will lie in wait.

The victory was no more than Sarries deserved after they outfought and outmuscled pretty much the same team that dished out a 30-3 drubbing in the EDF Energy Cup semi-finals a fortnight ago.

After James Hook had kicked his team ahead it was Sarries who took a 6-3 lead into the break thanks to a brace of Glen Jackson penalties. It was no more than they deserved after an abrasive performance, especially in the pack, had Ospreys rattled.

Alan Gaffney's men had structure, purpose and a swagger, epitomised by the brilliant Richard Haughton, and refused to let injuries to Andy Farrell and Brent Russell in quick succession disrupt their game plan.

And it was the two replacements that combined for Sarries' opening try a minute into the second half with Argentine Leonelli darting over from Adam Powell's pass as Ospreys stood and watched.

Jackson fired over his third penalty before a try for Ospreys replacement Paul James gave the visitors hope.

However, Jackson's late drop goal sealed a famous win for the brilliant hosts.

Hook kicked Ospreys ahead in the third minute after Richard Hill was penalised in front of his own posts.

Jackson was equal to the task in the 10th minute after Ospreys coughed up in front of goal following some patient Sarries pressure from a scrum on the visitors' 22 metre line.

The Men in Black edged ahead via Jackson's boot after 16 minutes following more disruptive work at the breakdown by the pysched-up home pack.

The Kiwi failed with his third attempt of the afternoon after Ospreys had infringed at the scrum as Sarries gathered momentum.

However, the hosts breathed a huge sigh of relief minutes later when, after an electric break through the centre by Hook, centre Sonny Parker knocked on with the line and a support runner at his mercy.

Haughton then got Sarries fans off their seats with a probing run down the right flank only for Russell to waste the opportunity by holding on. The wing was at it again minutes later, carving through a gaping hole in the middle of the park and riding several tackles before Hugh Vyvyan failed to grasp his low slung pass.

Sarries then suffered a double blow with Russell and Farrell forced off with what looked like a thigh and shoulder injuries respectively. Adam Powell came on for Farrell while Francisco Leonelli, last weekend's hat-trick hero against Leeds, moved to the right flank with Haughton filling the full-back berth.

Minutes before the interval more breathtaking running from Haughton, after anticipating Neil de Kock's rushed reverse pass saw Matt Cairns and Hugh Vyvyan gain ground before Paul Gustard fell inches short of the whitewash.

Sarries got the second half off to the perfect start when Leonelli raced to the whitewash from halfway after Powell collected de Kock's unorthodox clearance kick deep inside his own half. Jackson added the extras for 13-3.

Ospreys, backed by their fervent 5,000 supporters, came roaring back but Adam Jones spilled the ball as the Welshmen foraged in the left corner with powerful lock Alun-Wyn Jones at the heart of it.

Ospreys boss Lyn Jones then threw on Filo Tiatia, Richard Hibbard and Paul James for Jonathan Thomas, Huw Bennett and Duncan Jones respectively, while Sarries' flanker Don Barrell replaced Paul Gustard who was escorted from the field clutching his ribs.

During the rash of changes Vyvyan had been held up on the line as Sarries went for the jugular.

Ospreys full-back Lee Byrne was then sent to the sin bin for cynically blocking the ball with his arm as Sarries came storming forward yet again. Jackson nailed the penalty to leave the Ospreys needing two converted tries to sneak ahead.

Anything that could go wrong did go wrong for the Ospreys. Wing wizard Williams showed he is human after all when his woeful kick from halfway rolled under the posts dead.

A limping Leonelli then made way for scrum half Moses Rauluni, forcing de Kock onto the wing.

Ospreys, staring defeat in the face, cranked up the pressure and got their reward when replacement James barged over with five minutes left over despite the attentions of Barrell and Kevin Sorrell. Hook converted to reduce the gap to six points.

However, the mecurial Jackson booked his side's place in the last four with a confidently-taken drop goal to send the capacity crowd into raptures.

Saracens: Russell, Haughton, Sorrell, Farrell, Ratuvou, Jackson, de Kock (cpt); Lloyd, Cairns, Visagie, Vyvyan, Chesney, Gustard, Hill, Skirving.

Replacements: Leonelli for Russell, 30; Powell for Farrell, 32; Barrell for Gustard, 53; Rauluni for Leonelli, 69; Ongaro for Cairnss, Ryder for Chesney, 76.

Referee: Alan Lewis (Ireland).

Attendance: 18,214.

Scoring sequence: 0-3/3-3/6-3 HT/11-3/13-3/16-3/16-8/16-10/19-10.