Leeds come from behind to beat Derby in FA Cup action as West Ham earn rare win

Gabriel Martinelli's hat-trick saw Premier League leaders Arsenal overcome an early scare to beat Championship strugglers Portsmouth 4-1 in the FA Cup third round.

Portsmouth took a shock lead less than three minutes in through skipper Colby Bishop, but Andre Dozzell's own goal quickly levelled it.

Martinelli then took over, scoring either side of a missed penalty from Noni Madueke before completing his hat-trick in the 72nd minute.

Danny Welbeck scored the pick of the goals to dump out managerless Manchester United as Brighton won 2-1 at Old Trafford.

Brajan Gruda nodded in the opener 12 minutes in, and Welbeck rifled a left-footed strike into the top corner after the hour.

Benjamin Sesko pulled one back but United youngster Shea Lacey was sent off for a second bookable offence late on.

Willy Gnonto and Ao Tanaka scored within four minutes of one another as Leeds came from behind to beat Derby 3-1.

Ben Brereton Diaz put the hosts ahead after Joel Piroe's first-half penalty was saved, but after Gnonto and Tanaka turned it around, James Justin added a third.

West Ham's new £26million striker Taty Castellanos scored an extra-time winner to see off QPR 2-1 after Richard Kone had cancelled out Crysencio Summerville's opener.

Louis Reed scored twice against his former club as League One Mansfield upset Championship side Sheffield United with a 4-3 win at Bramall Lane, having led 4-1 before Patrick Bamford and a Nathan Moriah-Welsh own goal gave the Blades hope.

Jovon Makama's hat-trick powered Championship strugglers Norwich to a 5-1 win over Walsall, with Matej Jurasek and Tony Springett also on target.

Hull saw off Blackburn 4-3 on penalties after a poor goalless draw over 120 minutes, with Dillon Phillips denying Yuki Ohashi and Moussa Baradji from the spot.

Ollie Bostock hit the winning penalty as West Brom beat Swansea 6-5 on penalties after their match finished 2-2 in south Wales.