Brentford were knocked out of the Carabao Cup at the First Round stage by Cambridge United. The Sky Bet League Two side scored inside the opening minutes and held on until the later stages. An equaliser from Marcus Forss took the game to penalties but the visitors took it when it went to sudden death and made it in to the next round.

Cambridge battled manfully to hold on to a lead which was rather gifted to them by The Bees and then got over the line in the shoot-out. Emiliano Marcondes had one saved in the first five, but the shoot-out went to sudden death after Luke Daniels denied Paul Lewis. Luke Racic had his effort saved and Harvey Knibbs drilled the last kick home to send United through.

Brentford gifted the visitors a goal before three minutes had elapsed and before there had been a chance for any pattern of the game to be established. Dru Yearwood conceded possession deep inside his own half and a clever pass from Andrew Dallas gave Marc Richards yards of space inside the penalty area. There was a superb save from Daniels to keep out the first effort, but the ball came back to Richards and he lifted it past the stranded goalkeeper.

Brentford had barely conceded possession before the goal and took control of the game after it. Forss saw a shot blocked seconds after the restart and The Bees pressed forward to recover the deficit. Debutant Joel Valencia was at the centre of things in an attacking midfield role and he tried to bring full backs Josh Clarke and Dominic Thompson as well as his fellow attackers Forss, Jan Žambůrek and Bryan Mbeumo in to the game.

The Bees should have been level within three minutes when Žambůrek robbed Leon Davies and played the ball across the Cambridge penalty area. Mbeumo and Valencia arrived at the same time and the latter fired over the bar on the stretch from 15 yards. Thompson, on his professional debut, had a shot blocked and Valencia then saw a shot saved after picking up a pass from Yearwood and turning well.

Yearwood was starting to control the game in the centre of midfield and was able to regularly break through Cambridge’s midfield line and attack their increasingly deep five-man defence. He fired one effort over the bar and then had a shot deflect in to the path of Forss but the striker was crowded out as he attempted to finish from 15 yards. A Marcondes free kick troubled Callum Burton in the home goal but he did enough to keep it out.

As the half wore in, there was a sense of growing frustration from the Brentford players. They were on the front foot, playing almost exclusively in Cambridge’s half but mostly in front of the visiting defenders, who were well-organised and making few, if any, mistakes. There was a chance of a second for Cambridge when Dallas attempted a chip from 25 yards that flew well over and there were other occasions when a chance to break failed to materialise due to a poor pass from the visitors.

As Marcondes curled an effort well over in the dying seconds of the first half, it summed up the opening 45 minutes for The Bees – playing themselves in to attacking areas but unable to find the right final pass or shot. And that continued in to the early stages of the second half. Brentford had more of the ball but were unable to create the clear-cut opening to get themselves level.

And the home side could have been two down before the hour. George Taft failed to make connection at a free kick but as The Bees tried to break, Henrik Dalsgaard was robbed. The ball was worked by Taft to Dallas and he wriggled free before getting off a shot that Daniels saved well. The ball broke to George Maris and his shot looked set for the net before Racic made a block.

Žambůrek had seen a shot blocked just after the interval and a near post effort from Valencia was saved but Cambridge were looking more comfortable as the game progressed. Mathias Jensen was introduced early in the second period as The Bees tried to change the flow of the game and Ollie Watkins followed just past the hour mark. And those changes did have the desired effect as Brentford levelled with 20 minutes remaining.

There was an immediate impact after the substitutions. Watkins gave an extra attacking outlet and more precision in the final third while Jensen moved the ball in a more efficient manner. There was a more coherent approach to Brentford’s play, particularly in attack and chances came.

A Dalsgaard effort from a corner flew over and a shot from Rico Henry – on in the first half when Clarke limped off and doing a superb job as an attacking right back – whizzed a fraction too high. A clever pass from Jensen was met on the volley by Mbeumo but Burton saved low down and the resulting corner was, after a ricochet, put over the bar by Racic, who attempted an acrobatic effort. But the goal came moments later when Watkins found space in the inside left channel and, after he sorted his feet, delivered a cross for Forss to meet at the near post, firing home off the post.

From then on, it was a matter of whether Cambridge could hold on for a penalty shoot-out. Henry had a shot blocked and then, when the ball was recycled and returned to him by Jensen, he curled a shot inches past the far post. Marcondes saw a shot blocked after he picked up a clever pass from Watkins and a Mbeumo effort was deflected in to the arms of Burton. Valencia could have won it at the death when he picked up a Jensen pass, but he lashed over from just outside the penalty area and that meant it went to penalties.

Both teams missed their second but Jensen, Mbeumo, Watkins and Forss scored for The Bees. Burton saved from Marcondes, away to his left, but Daniels ensured it was level after five with a brilliant stop from Lewis, pushing the effort on to the post. And he almost saved Cambridge’s fifth from Harry Darling, the ball squirming underneath and bouncing in to the net. Racic blasted his down the middle and Burton stood still to save enabling Knibbs to fire low and send Cambridge through.

Brentford: Daniels; Clarke (sub Henry 33 mins), Dalsgaard, Racic, Thompson; Yearwood (sub Jensen 55 mins), Marcondes; Mbeumo, Valencia, Žambůrek (sub Watkins 64 mins); Forss

Subs (not used): Gunnarsson, Hammar, Oksanen, Canós, Watkins

Bookings: Thompson (18 mins)

Cambridge United: Burton; Davies, Darling, John, Taft, Dunk; Lambe, Lewis, Maris (sub Hannant 72 mins); Richards (sub Knibbs 60 mins), Dallas (sub Jones 72 mins)

Subs (not used): Mitov, Jones, Taylor, Hannant, Knowles

Bookings: John (19 mins)

Attendance: 5,215 (706 away fans)