Middlesbrough lacking momentum as they crash out of FA Cup against classy Brighton

World Cup winner Alexis Mac Allister scored his first goals since returning from Qatar as Brighton eased to a 5-1 victory at the Riverside Stadium to reach the fourth round.

The Argentina international, a half-time replacement for Adam Lallana at the Riverside Stadium, produced deft 58th-minute and 80th-minute finishes to cement a comfortable 5-1 victory for the Premier League side.

First-half goals from Pascal Gross and Lallana either side of Chuba Akpom’s equaliser – his 14th of the season – had set the visitors on their way.

Substitute Deniz Undav added a late fifth on a day when Michael Carrick’s promotion hopefuls were given a taste of what awaits them should they make it out of the second tier this season.

“I knew before the game how good they were,” said Carrick. “We’ve obviously watched a lot of them and those who hadn’t probably seen much of them maybe didn’t appreciate how good they have become at the moment, so we knew who were up against.

“For long spells in the game I thought we did really well, actually, and we still felt and looked like we had a threat in the first half, especially on the break.

“Obviously the quality was there for everyone to see but in those type of games you need certain moments and certain momentum shifts in the game.

“You just need those moments to change the course of the game, really, and we didn’t quite get it and towards the end, obviously it becomes difficult.”

It was skipper Gross who made the breakthrough with just eight minutes gone when, after the unmarked Solly March had run on to Evan Ferguson’s intelligent pass to force Zack Steffen to save, he followed up and slotted into the empty net.

The Teessiders were struggling but got themselves level after 13 minutes when former Boro goalkeeper Jason Steele couldn’t quite stop Akpom’s header.

Steffen was picking the ball out of his net once again on the half-hour when Mitoma fed March’s cross back to the far post and Lallana headed home from point-blank range. He then had to deal with a well-struck Mitoma effort to ensure the hosts went in at the break just a single goal in deficit.

Mac Allister replaced Lallana at the interval as the visitors returned in determined mood and they could have killed the game off within three minutes had March not directed a free header from Pervis Estupinan’s inviting cross straight at Steffen.

The hosts could simply not escape their own half with Moises Caicedo and Mac Allister dominating the middle of the park and the Argentinian got his reward when he reacted smartly to flick Estupinan’s raking shot past Steffen and inside his left post.

Mac Allister twice went close with free-kicks and eventually doubled his tally when he converted Gross’ low cross with the minimum of fuss before Undav completed the job with two minutes remaining.

Middlesbrough: Steffen, Smith, Fry, McNair, Giles (Bola 81), Forss (Watmore 59), Howson, Hackney (Mowatt 59), McGree (Jones 59), Akpom, Crooks (Archer 68). Unused substitutes: R Muniz, Hoppe, Roberts, Gitau.

Brighton & Hove Albion: Steele, Lamptey, van Hecke, Colwill (Webster 81), Estupinan, Caicedo, Gross (Undav 81), March, Lallana (Mac Allister 46), Mitoma (Enciso 64), Ferguson (Welbeck 64). Unused substitutes: Sarmiento, Gilmour, Veltman, McGill.

Referee: Simon Hooper (Wiltshire).