The Vetch Field was in full impassioned song long before the end as Third Division Swansea knocked tormented West Ham out of the FA Cup last night to earn a home tie with Derby County in the next round.

A goal by Martin Thomas in the first half was enough but it still took a superb late save by Roger Freestone from Neil Ruddock to thwart West Ham.

Julian Dicks may have made his peace this week with his manager over his supposed outspoken views - he did ensure the replay with a 30-yard goal at Upton Park - but there were anxious expressions among the West Ham faithful for his unsubtle confrontation with Stuart Roberts. There was much baying for blood but he escaped with a caution.

The more impressive attacking play early on had come exclusively from the London club. Too often however they ran into trouble against the solid defensive barrier put up by Jason Smith and Matthew Bound. John Hartson, maybe again suffering from the lack of balance in West Ham's attack, was making a sentimental rather that fruitful return to his birthplace.

Thomas's influence, like that of his skipper Nick Cusack, became more apparent as Swansea came to terms with the ploys of their opponents. Manny Omoyimni was booked in trying to stop Thomas who later saw his free-kick spin off the angle of the bar as the visitors' defence faltered.

Swansea were following to the letter the tight-marking though fluid game advocated by John Hollins, their manager. They successfully dealt with the now modest raids of West Ham and in their brightest spell so far took the lead after 29 minutes.

Cusack and Jonathan Coates had worked the ball intelligently and it was Thomas who ultimately scored with a shot from just outside the area. West Ham, forced to reshuffle because of injuries, appeared increasingly frustrated as in their first meeting, by the vigour and heart of the Welsh side.

Harry Redknapp's men tried to rediscover the creative inroads they made in the first 20 minutes and, in truth, there was little wrong with defenders Rio Ferdinand and Neil Ruddock who blocked Swansea's brave burly leader Julian Alsop, who was working on a building site in Coventry not long ago. It was Roberts's pacy bursts on the right and some superb persistence by Thomas which bothered West Ham most.

Swansea manager John Hollins hailed his team of FA Cup heroes after their shock 1-0 victory over Premiership West Ham in a thrilling clash at the Vetch Field.

Afterwards Redknapp said: "It's been disappointing because I was hoping for a good Cup run like we had last year in both competitions. I felt we had enough chances that we should have scored tonight."

Swansea: Freestone, S Jones, Howard, Cusack, Smith, Bound, Coates, Thomas, Alsop, Watkin, Roberts. Subs Not Used: Price, J Jones, Newhouse, Lacey, Casey. Booked: Howard, Cusack, Bound, Freestone. Goal: Thomas 29.

West Ham: Hislop, Ruddock, Ferdinand, Dicks, Breacker (Hall 72), Lampard, Lomas, Lazaridis, Omoyimni (Berkovic 45), Hartson, Sinclair. Subs Not Used: Forrest, Abou, Potts. Booked: Omoyimni, Dicks, Breacker, Sinclair.

Referee: S Lodge (Barnsley).