Hall has a ball.
Hall top-scored with a quickfire 39 to haul Northants to 134 for six before taking best bowling figures of three for 25 as Hampshire collapsed.
Once dangerman Dimitri Mascarenhas fell to Johan van der Wath, the Friends Provident Trophy winners lost four wickets in eight balls as Northants booked a semi-final match against Sussex.
Hampshire captain Mascarenhas put Northants into bat and his decision paid off when he dismissed Stephen Peters for a duck who flashed a shot straight to Chris Benham.
It got better in the next over as Dominic Cork, picking up where he left off on Saturday, forced Rob White (5) to edge to wicketkeeper Tom Burrows.
Mascarenhas soon picked his second wicket and the scalp of captain Nicky Boje for five as Liam Dawson took a great catch at cover to leave the home side wobbling on 16 for three.
And despite being reduced to 82 for six, an unbeaten seventhwicket partnership of 52 between Hall and Van der Wath, 14, saw Northants post a respectable score.