West Ham United picked up their first piece of silverware of the new season as the Under-18s lifted the Southend United U19 Youth Cup.
Having defeated the hosts in a thrilling penalty shoot-out on Saturday, the Hammers returned to Roots Hall on Sunday afternoon to face reigning FA Premier Academy League champions Arsenal.
The Gunners, who beat Dutch side FC Twente in the semi-finals, went into the final as favourites, only for West Ham to upset their north London rivals to the tune of a 2-1 victory.
Both sides missed chances in the early stages before Arsenal took the lead. Jack Werndly, who had returned from reserve-team duty at Burton Albion on Saturday, then passed up an opportunity to level the score.
Another of Saturday's reserve-team squad, Danny Subuola, was not so profligate, firing a low shot into the corner to send the two teams in 1-1 at half-time.
Captained by centre-back Paco Craig, the Hammers continued to press after the break, with first-year scholar Kenzer Lee firing narrowly wide.
The winner arrived in rather fortunate circumstances when Blair Turgott's shot was turned past his own goalkeeper by an Arsenal defender.
England U17 forward Robert Hall could even afford the luxury of missing a superb chance to add a third goal late on as West Ham held on comfortably to secure the trophy for Paul Hilton's side.
The U18s will go into the remainder of their pre-season schedule full of confidence ahead of the start of the FA Premier Academy League season on Saturday 21 August.
Trips to non-league Great Wakering Rovers on Wednesday 28 July and Heybridge Swifts on Saturday 31 July are next up.
Ipswich Town will welcome the Hammers on Wednesday 4 August before Academy Director Tony Carr's squad make the short trip to Leyton Orient on Saturday 7 August.
The U18s complete their schedule with away games at Hornchurch on Tuesday 10 August and Norwich City on Saturday 14 August.
West Ham ended the 2009/10 campaign fifth in the ten-team Group A table, winning ten, drawing eight and losing ten of their 28 league matches. The Hammers also reached the FA Youth Cup fifth round, beating Plymouth Argyle and Queens Park Rangers before being knocked out by Newcastle United.