It was meant to be Angus Fraser's big day, but Sussex spoiled the Middlesex captain's last match at Lord's with an admirable performance.

The county booked a third successive appearance in the quarter-finals of the Benson and Hedges Cup after beating Middlesex for only the second time in the competition since 1973.

Richard Montgomerie (85) and Tim Ambrose (56) laid the foundations with a first-wicket stand of 139 as Sussex made 252-6 from their 50 overs before Billy Taylor and Robin Martin-Jenkins wrecked the reply by taking three wickets each as the hosts were reduced to 62-7.

David Nash and Ashley Noffke saved Middlesex from total embarrassment with an entertaining eighth-wicket stand of 112 in 17 overs before Taylor, who won the gold award for his 5-28, wrapped up victory by 28 runs with nine balls to spare.

On his penultimate day as a county cricketer Fraser, who retires after today's game against Hampshire to take a job in the media, didn't even have the satisfaction of a taking a wicket in his final game at headquarters.

An unusually animated Lord's crowd roared each time Fraser chugged in from the Nursery End to bowl his final over, but being slogged through mid-wicket by Will House probably wasn't quite how he envisaged it would all end.

But judging by the fare served up by his team-mates, Middlesex are going to struggle desperately to replace him.

That won't worry Sussex, of course. After a false start against Essex last week, the county have reeled off three wins and there is a growing belief among the players that they are capable of progressing even further than the last eight in the final year of a competition in which they have never reached the final.

They largely outplayed Middlesex, the tone set by a second-century partnership in three games from Montgomerie and Ambrose.

Fraser used the new ball well, but his colleagues spent too much time feeding the batsmen's favourite areas on the leg side and Sussex were able to cruise along at five runs an over throughout their innings.

The sight of wicketkeeper Nash standing up to Fraser was an indication of just how little pace there was in the pitch, but the Sussex pair improvised well.

Montgomerie came down the pitch to drive over the infield while Ambrose grew in confidence after a scratchy start, reaching his fifty off four more balls than his partner's 73.

Ambrose fell first when he mis-timed a pull off Simon Cook after making 56 in 86 balls with six fours, but Montgomerie accelerated after reaching his half-century and was closing in on a second successive hundred at Lord's when he was sent back by Murray Goodwin after clipping the ball straight to mid-wicket and setting off for a single that was never on. Ben Hutton's sprawling throw did the rest, Montgomerie's 85 having come off 113 balls with eight fours.

Goodwin was unhinged by a ball from Cook which nipped back and kept low and Chris Adams lost three partners in the last five overs while making sure, with another responsible innings, that his side didn't lose any of their momentum.

House was caught at backward point off a top-edged slog, Tony Cottey holed out to mid-on and Martin-Jenkins, having just hit successive fours, was taken at the wicket off a thick edge trying to find the boundary again in the last over.

Adams only hit two boundaries, but his 40 was still scored at more than a run a ball.

James Kirtley has already taken 12 wickets in three B and H ties but, although he went wicketless on this occasion, Martin-Jenkins and Taylor proved a more than capable support act.

Impatience got the better of Andrew Strauss, Fraser's successor as captain, when he pulled Martin-Jenkins straight down the throat of Michael Yardy on the square-leg boundary in the sixth over, but his wasn't the only indiscretion by Middlesex's top order batsmen.

Taylor replaced Kirtley in the 11th and struck twice in his second over. Hutton was caught behind pushing tentatively at a ball which did just enough off the seam and Taylor then claimed the key wicket of Owais Shah who was defeated by late inswing.

Ed Joyce became Martin-Jenkins' second victim propping half-forward and Middlesex had lost half their side in the 22nd over when Mark Davis snared South African opener Sven Koenig, courtesy of a superb catch by Montgomerie as he raced in from the mid-wicket boundary.

When Cook clipped Taylor straight to mid-wicket in the 25th over Middlesex were 62-7 and Fraser's day was in danger of ending in embarrassment.

But for a while Sussex lost their discipline in the field as Nash and Australian Ashley Noffke put on 112, a competition record for the eighth wicket. The ground fielding lost it's earlier snap and Yardy, House and Davis conceded 124 runs between them in 20 overs.

In the same Kirtley over, Noffke was dropped by Taylor in front of the pavilion and would have been run out had the bowler not dropped Adams' throw from mid-wicket with the batsman scrambling to make his ground.

The asking rate never dipped below eight an over and Noffke's fun ended when he pulled House to deep square leg having made 57 entertaining runs off 55 balls with three fours and a six off Davis over long on.

Chad Keegan helped Nash to a limited overs career-best before he was yorked by Taylor off the first ball of the penultimate over.

All of which left the stage clear for Fraser to walk out at his beloved Lord's for the last time to a standing ovation from the crowd and a guard of honour from the Sussex players.

He had the satisfaction of finishing with a not out after scrambling a single before returning to the pavilion to another standing ovation after Taylor became the third Sussex player to claim career-best limited overs figures in the space of a week when he bowled Nash for 60.