Letcombe came from three goals down at half-time to win 4-3 at Maidenhead United Res in Division 1 East of the Uhlsport Hellenic League.
Trailing to an Athoney Mendy double and a Benjamin Amos strike, Letcombe stormed back in the second half.
Adam Bruce curled a free-kick into the top corner, Adam Claydon netted from close range and Adam Pendell equalised, before Bruce grabbed the winner six minutes from time.
Abingdon United Res won 3-1 at home to high-flying Newbury.
Steve Andrews, Francesco Merola and Drew Fowler struck in a six-minute spell from the 70th minute after Darren Jones had given Newbury a 15th-minute lead.
Chinnor slipped to a 3-0 defeat at home to second-placed Chalfont Wasps.
Simon Williams, John Mason and Fred Tripp did the damage.
Clanfield were crushed 6-1 at runaway Division 1 West leaders Tytherington Rocks.
Tony Perry, Alex Chapman and Dale Emery put Tytherington in charge at half-time.
Rocks had keeper Tom Sheppard sent off for denying Robbie Harrington a clear scoring opportunity after the break.
But despite this the hosts scored three more through Tim Baker and a Toby Colbourne double, before Steve Olphert pulled one back in the last minute.
James Luckett scrambled an 85th-minute equaliser to give Headington Amateurs a 2-2 draw at Cirencester Town Development.
Josh Morse had given Cirencester a fourth-minute lead, before Luke Cuff equalised with a spectacular strike from a narrow angle in the 27th minute.
Danny Hale restored Cirencester’s advantage in the 48th minute, before Headington keeper Harry Jenkins produced a stunning penalty save. Hook Norton’s recent good run came to an end with a 4-3 home defeat by New College, Swindon.
Mark Dennis, Jason Tillcock and Reve Barsanti netted for Hook Norton, but a Josh Skeates hat-trick and a Jake Johns goal gave the students the edge.
Carterton Town’s poor season continued with a 3-1 home defeat by Winterbourne United.
Barry Morton opened the scoring for Carterton, but a Jack Pitcher hat-trick gave Winterbourne the points.
Easington Sports were held to a 1-1 draw at Wootton Bassett Town.
James Trevitt opend the scoring for Easington in the 62nd minute, but Matt Bown equalised 13 minutes later.
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