Hampshire's dreams of adding a Twenty20 Cup success to their Friends Provident Trophy triumph were dashed at Northampton.
Five days after beating Sussex at Lord's to claim domestic cricket's first prize of the summer, Hampshire came up short by 13 runs at Wantage Road after Northants had totalled 134 for six.
The home side appeared to be in serious trouble at 16 for three, and again at 82 for six, but South Africans Andrew Hall and Johan van der Wath fought back strongly with an unbroken stand of 54.
Not content with that, the pair then shared five wickets as Hampshire struggled to make decent progress.
Van der Wath eventually claimed the key scalp of Dimitri Mascarenhas for 36.
Hampshire were then 121 for seven and they lost their last three wickets without addition as Hall and his countryman gleefully cleaned up the tail.
Northants face Sussex in one of the semi-finals at Edgbaston on 15 August while the other clash will be between Somerset and Kent.
Somerset beat Lancashire in a bowl-out at Old Trafford after their quarter-final had been washed out for a third consecutive day.
And the shoot-out wasn't even close, with the visitors winning 5-1.
The winners of the two semi-finals at Edgbaston will qualify for the first Champions League Twenty20, to be staged in India in October.
That 12-team event will include sides from Australia, South Africa, the West Indies, New Zealand and India, as well as England, and will have a total prize fund of around £4million.
