Somerset needed the final ball of their innings to secure a one-run win over Hampshire, claiming just their second victory of the season.
Michael Carberry hit 38 off 24 balls to lead the visitors to 175 in their innings, but Craig Meschede managed to edge the hosts ahead off the last delivery.
A knock of 60 from Johnny Bairstow led Yorkshire Vikings to an 18-run victory in their meeting with Northamptonshire, leaving them third in the North Group standings.
The wicketkeeper hit the total off 37 balls as Yorkshire set their opponents a target of 182.
Opening batsman Richard Levi get the hosts off to a good start as they tried to chase down the total, but his 76 was not enough.
A couple of late wickets from Recordo Gordon helped Birmingham Bears to an 18-run win over Nottinghamshire Outlaws.
The home side were chasing 157 for victory, and were in with a chance until Gordon removed Steven Mullaney and James Taylor in the 17th over.
Lancashire Lightning finished strongly with the ball to take a nine-run win over Leicestershire Foxes to remain level on points with Northern leaders Worcestershire.
The visitors were chasing 167 for the win, but Tom Wells and Robert Taylor were both dismissed inside the final two overs to allow Lancashire to hold on for the win.
Surrey clinched a 10-wicket win over Sussex Sharks, allowing them to move above their opponents in the South Group standings.
Opening batsmen Hashim Amla and Jason Roy finished Surrey's innings not out as they passed Sussex's total of 148 with more than four overs to spare.
Essex Eagles have claimed an eight-wicket win in their match against Gloucester to maintain their lead at the top of the South table.
Hamish Marshall led Gloucester's innings as they set the home side a target of 163 for victory.
However, a 112-run partnership from Ravi Bopara and Tom Westley ensured that Essex reached the total with just under two overs to spare.
Worcestershire Rapids were too strong for Derbyshire Falcons, beating their opponents by eight runs.
Daryl Mitchell and Colin Munro both hit half-centuries for Worcestershire as they reached 177-5 off their 20 overs.
However, Christopher Russell ensured that Derbyshire's reply came up short, claiming four wickets, while Jack Shantry took three.
Glamorgan and Kent Spitfires could not be separated, both posting totals of 177 during their innings as they played to a draw.
Darren Stevens was the pick of the batsmen for Kent with a knock of 71, including six sixes, while James Allenby had a half-century for Glamorgan.
Sian Cowper
