Managerless Manchester United’s season took another turn for the worse as they were knocked out of the FA Cup by Brighton on Sunday.

Arsenal continue to challenge on four fronts after they came from behind to beat Portsmouth 4-1 with a Gabriel Martinelli hat-trick while Scottish Premiership leaders Hearts claimed a crucial 1-0 win at Dundee.

Welbeck adds to former club’s woes

United’s whirlwind week ended on a low note as Danny Welbeck helped shoot down his former club at Old Trafford.

Welbeck was on the scoresheet as Brighton won 2-1 in the FA Cup third round, compounding United’s woes after manager Ruben Amorim was sacked last Monday.

Welbeck added to Brajan Gruda’s opener to put the Seagulls on course for a first victory over United in the competition.

Benjamin Sesko’s header gave United, under the caretaker charge of Darren Fletcher, late hope but Red Devils teenager Shea Lacey was sent off soon after and Brighton held on.

Martinelli grabs hat-trick as Gunners hit back

Arsenal’s Gabriel Martinelli celebrates scoring one of his three goals against Portsmouth
Gabriel Martinelli hit three against Pompey (Andrew Matthews/PA)

Gabriel Martinelli hit the headlines for the right reasons by scoring a treble as Arsenal overcame an early scare to thrash Championship strugglers Pompey 4-1 in their third-round tie.

The Premier League leaders fell behind less than three minutes into a rain-soaked contest at Fratton Park when Colby Bishop finished from close range.

Andre Dozzell’s own goal quickly levelled the contest before Brazil forward Martinelli struck either side of Noni Madueke’s penalty miss.

Martinelli, who was widely criticised for attempting to push the injured Conor Bradley off the pitch during Thursday’s goalless draw with Liverpool, completed his hat-trick in the 72nd minute.

Hammers avoid cup embarrassment

West Ham United’s Taty Castellanos (right) celebrates scoring a winning goal against QPR
New signing Taty Castellanos spared West Ham’s blushes (Bradley Collyer/PA)

Taty Castellanos scored an extra-time winner as West Ham avoided an embarrassing FA Cup exit by edging past QPR 2-1.

The Argentinian was brought in for £26million from Lazio last week in a bid to salvage the relegation-threatened Hammers’ terrible Premier League season.

That may yet prove beyond him, but Castellanos did at least take their cup campaign beyond the third round with his first goal for the club.

Richard Kone had earlier cancelled out Crysencio Summerville’s opener as Rangers briefly threatened to produce a shock.

Leeds also avoided an upset as they came from behind to win 3-1 at Derby.

Gordon comes off bench to keep Hearts bid on track

Craig Gordon celebrates Hearts' victory over Dundee
Veteran goalkeeper Craig Gordon ensured Hearts held on at Dundee (Steve Welsh/PA)

William Hill Premiership leaders Hearts demonstrated their title credentials by overcoming a red card for goalkeeper Alexander Schwolow to grind out a 1-0 victory away to Dundee.

In front of a 4,000-strong travelling support, the Jambos went ahead through Claudio Braga’s 27th-minute strike.

The wind was removed from the visitors’ sails when Schwolow was sent off in first-half stoppage time for fouling Tony Yogane.

But Scotland goalkeeper Craig Gordon came on for his first Jambos appearance of the season and helped secure a potentially huge victory by pulling off a stunning stoppage-time save from Emile Acquah.

What’s on today?

The FA Cup third round continues as Liverpool host League One Barnsley. The draw for the fourth round also takes place.