THIRTY seasons on from their Milk Cup triumph, Oxford United began the latest edition of the competition by causing the shock of the first round to embarrass Championship side Brentford.

The astonishing scoreline owed much to an explosive start, where the underdogs raced into a 3-0 lead against after just 12 minutes.

Attacking excellence and some shambolic defending saw Liam Sercombe, Danny Hylton and Kemar Roofe, who struck from 45 yards, all find the net.

Johnny Mullins added a fourth in front of 903 ecstatic away fans after half-time to kill the tie off and secure United's safe passage into Thursday's second round draw.

The teamsheet delivered surprises from both sides. Michael Appleton, who had said in the build-up he would make changes, named the same side which began Saturday's 1-1 draw with Crawley.

By contrast, Brentford changed their entire XI, handing debuts to five players promoted from the development side.

Within 12 minutes the selection had backfired spectacularly, as the youngsters were overrun by a rampant United side.

The Bees defence had already looked shaky when, in the fifth minute, Andreas Bjelland's poor clearance fell to Sercombe 20 yards out.

The midfielder took a touch to steady himself, before drilling a fierce low shot past Jack Bonham for his first United goal.

It rapidly got much worse for the 21-year-old goalkeeper, who was making only his third senior start.

There were nine minutes on the clock when Hylton chased down a backpass, panicking Bonham into a clearance which struck the forward and ricocheted into the net.

A large away contingent were in dreamland, but incredibly within three minutes it got even better, when Bonham came out of his area to head a through ball straight to Roofe.

The winger was at least 40 yards out, but his control and shot were exquisite to return the ball over the keeper's head and into the net.

Brentford's unfamiliar line-up were dazed and it took them until the very end of the half to muster any attacking pressure, which the visitors dealt with.

Roofe was taken off at the break, perhaps with a view to Saturday's trip to Luton Town, but United did not take their foot off the pedal.

Substitute Callum O'Dowda took nine minutes to make a telling impact, bringing down Alex MacDonald's high cross and setting up Mullins to make it 4-0 from ten yards.

Any hopes Brentford may have had about staging a comeback promptly vanished.

There was still more an half an hour to play, but the contest was over.

Brentford (4-3-3): Bonham, Clarke, Bjelland (Bidwell ht), Barbet, O'Connell, Williams, Yennaris (McCormack 53), Laurent, Udumaga, Vibe, Senior. Unused subs: Smith, Kerschbaumer, Gogia. Booked: None.

Oxford Utd (4-4-2): Slocombe, Baldock, Mullins, Wright, Skarz, Roofe, Sercombe, Rose, MacDonald, Hylton, Taylor. Subs used: O'Dowda (Roofe ht), Ruffels (MacDonald 59), Hoban (Taylor 64). Unused subs: Crocombe, Dunkley, Long, Ashby. Booked: MacDonald, Sercombe.

Referee: Dean Whitestone (Northamptonshire).

Attendance: 5,177 (903 visitors).