SARACENS all but assured their first ever Heineken Cup quarter-final after sending out 2006 finalists Biarritz with an amazing 45-16 bonus point victory at Vicarage Road this afternoon.

The Men in Black head to Glasgow for next friday's group game five points ahead of the Magners League outfit. If they reproduce this kind of performance who knows how far they can go in the competition.

Hugh Vyvyan's converted try on the stroke of half time ensured the Men in Black headed into the dressing room all square at 13-13. Jackson had notched a penalty either side of a Romain Cabannes score and Julien Dupuy penalty, the French scrum-half adding another before Vyvyan's powerful effort.

Chris Jack's first Sarries try put them in command at 23-13 before Dupuy kept his side in the hunt with another penalty.

Rodd Penney's try on the hour saw Sarries extend their lead to 30-16 before Jack's second try of the game sewed up the bonus point.

A late penalty try merely rubbed salt in the wounds of the visitors while underlining Sarries' second half dominance.

Sarries never looked like a side who had lost their last two league games, while the noise emanating from the ground at the final whistle was deafening.

An infectious, nervous start was underlined by some wayward kicking from Biarritz full-back Nicolas Brusque and Neil de Kock, before Richard Haughton warmed up the crowd with a typical jinking run from his own 22.

Sarries showed how fired up they were for this one with some patient, solid defending after Ben Skirving's pass was intercepted by Julien Dupuy, the outcome a penalty after Brusque had held on.

Jackson fired Sarries ahead with a 15th minute penalty after Biarritz had infringed at a far-side line-out.

However, the lead lasted barely 30 seconds as Andy Farrell's laxadaisical clerance kick was charged down by centre Cabannes, who kicked on to score in the right corner. Dupuy added the extras before landing a superb penalty from the half-way line to make it 3-10.

The Sarries faithful then held its breath as de Kock's attempted clearance from the back of a ruck was charged down by Dupuy, who engaged in a foot race for the ball with Jackson. However, the ball bobbled out of of play with Jackson's momentum taking him into the advertising boards.

The Kiwi and Dupuy traded penalties in quick succession as the intensity of the first 20 minutes petered out.

From the restart the Men in Black foraged for an opening but Cencus Johnston's knock-on against his former team saw a rare chance go begging.

However, Sarries kept their composure and landed a psychological blow on the stroke of half time. After good work from Farrell, Kris Chesney tried a pick and run before the ball was worked out right for Jackson. The fly-half sold an exquisite dummy to his marker before off-loading for Vyvyan to crash over for his sixth try of the season.

Jackson added the extras to make it 13-13 at the break - unlucky for someone, but who?

Well, it was the hosts who were cursing their luck three minutes into the second half when referee Nigel Fox, after consulting the TMO, denied Richard Haughton a try after the man upstairs had adjudged the wing had knocked on before collapsing on the ball in the right corner.

It was harsh on Sarries who produced their best period of the game in the build up with Nick Lloyd, Brent Russell and Farrell showing some intuitive running after Rodd Penney had masterminded the turnover at his side's 22 metre line.

Nevertheless, the hosts kept plugging away and regained the lead through Jackson's third penalty of the afternoon.

It got better for the hosts minutes later when Jack snaffled the loose ball at a ruck before piroetting away from Imaanol Harinordoquy to score his first try for the club.

Dupuy then nailed his third penalty of the game after Johnston had killed the ball.

Then came a sublime piece of skill which set up Penney for Sarries' third try. After Farrell was hauled down by three Biarritz players, de Kock picked up and delivered an instinctive one-handed reverse pass to Penney, who left both Harinordoquy and replacement Serge Betsen in his wake en route to the whitewash.

Yet more Sarries pressure culminated an another easy penalty for Jackson, who played on through the pain barrier after taking a knock to his right ankle.

Biarritz flanker Betsen, roundly booed by the home fans, was then sent to the cooler for use of the boot.

Sarries took advantage and Jack ploughed over for his second try to ensure that all-important fifth point for the hosts.

Referee Owens awarded the hosts a last minute penalty try and the magnificent Brent Russell converted in the absence of the substituted Jackson to complete a memorable victory.

Saracens: Russell, Haughton, Sorrell, Farrell, Penney, Jackson, de Kock (cpt); Lloyd, Ongaro, Johnston, Jack, Vyvyan, Chesney, Hill, Skirving.

Replacements: Powell for Farrell, 74; Gustard for Skirving, Mercey for Johnston, Ratuvou for Jackson, Dickens for de Kock, 79; Kyriacou for Ongaro, Ryder for Vyvyan, 80.

Biarritz: Brusque, Bidabe, Cabannes, Traille, Ngwenya, Peyrelongue, Dupuy; Balan, August, Avril, Thion (cpt), Hall, Vahafolau, Hardinordoquy, Cronje.

Replacements: Lecouls for Balan, 32; Masi for Traille, 45; Balan for Lecouls, Betsen for Vahafolau, 54; Thiery for Ngenya, 55; Niorot for August, 64.

Referee: Nigel Owens.

Attendance: 8,656.

Scoring sequence: 3-0/3-5/3-7/3-10/6-10/6-13/11-13/13-13 HT/16-13/21-13/23-13/23-16/28-16/30-16/33-16/38-16/43-16/45-16.