The Newcastle United midfielder, who has been on loan at the One Call Stadium since January, started for Nigel Clough's men under the arch as they bid to cap an excellent season with promotion to the third tier.

But the Stags fell behind early on as Kian Harratt put Vale in front before James Wilson made it 2-0 on 24 minutes, leaving the 22-year-old and his side with plenty of work to do.

Their task became even more difficult ten minutes before the break when Ollie Hawkins was dismissed after two quickfire bookings, leaving Mansfield a man light.

Rhys Oates went close but there was no way back for Town, with Mal Benning's late effort adding extra gloss to the scoreline and confirming the Valiants' promotion to League One.

Before his disappointing first outing at Wembley, Longstaff – who was replaced by George Maris 25 minutes from time – had enjoyed a productive loan spell after making the move to the East Midlands on deadline day, making 18 appearances, registering six goals and two assists to help propel the the Stags into promotion contention.