Erik ten Hag wants Manchester United to be more ruthless but insisted a frustrating first Premier League loss of the season was far from doom and gloom.

United were beaten 2-1 at Brighton on Saturday after a late defensive lapse led to unmarked Seagulls striker Joao Pedro heading home in the fifth minute of added time.

Amad Diallo cancelled out Danny Welbeck’s opener at the Amex Stadium before Joshua Zirkzee inadvertently prevented the visitors taking a 70th-minute lead by touching Alejandro Garnacho’s goal-bound effort over the line from an offside position.

United, who required an 87th-minute debut goal from Zirkzee to beat Fulham 1-0 on the opening weekend, host rivals Liverpool next Sunday, with manager Ten Hag seeking improvements.

“In build-up and in possession and in how we defend, I have seen some good parts,” he said.

“Also there were parts in the game, especially from the second half, where we should keep more control.

“There were very good parts in this game so I have seen a lot of positives from the performance.

“But we have to build up, in both boxes we have to be more clinical there, we have to be more aggressive.”

Albion forward Welbeck claimed his 100th career goal – and sixth in 16 appearances against his former club – in the 32nd minute and later headed against the crossbar.

Diallo’s deflected 60th-minute equaliser shifted the momentum in United’s favour, only for Garnacho to be thwarted by fellow substitute Zirkzee before the misfortune was compounded when Pedro pounced at the death.

United goalkeeper Andre Onana called for the team to quickly set aside their frustrations.

“We had a great game, I think we were better than them, we had more chances, we had more possession, we had more control of the game,” Onana told manutd.com.

“Unfortunately, they disallowed us a goal, but that’s part of football, that’s part of life, we have to move on.

“Big games are coming, big clubs, so the expectation is here, it will be very high. We have to get ready again for the games that are coming.”

Brighton built on last weekend’s 3-0 win at Everton to maintain their 100 per cent start under new head coach Fabian Hurzeler.

“It’s always difficult to describe emotions because they are massive, they are so positive,” said the 31-year-old German.

“That’s why I love to do this job because you can’t buy these emotions and you won’t get these emotions through anything else.”

Hurzeler also praised the influence of 33-year-old ex-England international Welbeck following his landmark goal.

“It’s an amazing achievement,” he said. “Danny’s a role model – I can learn also from him because he went through experiences I never made as a player.

“That’s why I share some talks with him. I share my opinions, he shares his opinions. He’s a great team-mate, he’s like a connector, he’s trying to help everyone.

“He’s paying attention a lot in the locker room and it is enjoyable to work with him and to have good conversations with him.”