Yorkshire Vikings beat Lancashire Lightning by nine runs at Headingley
Kent Spitfires beat Surrey by 11 runs to stay top of South Group
Holders Notts Outlaws on verge of quarter-finals after big win over Birmingham Bears
Also wins for Somerset, Hampshire, Sussex, Leicestershire and Worcestershire
As usual, our BBC local radio teams are in place to bring you ball-by-ball coverage of the eight games this evening. Choose a commentary from the audio promos at the top of the page and while you're listening, we'll provide you with regular text updates on the other matches.
Image source, Rex FeaturesT20 Blast (Matches start at 17:30 BST, 18:30 and 19:00)
Image source, Rex FeaturesIt's first v second on South group this evening as leaders Surrey take on Kent Spitfires in Canterbury.
They are level on 13 points, one point clear of Gloucestershire and Somerset, and Surrey are boosted by the return of Jordan Clark following the birth of a child earlier this week.
In North group, Notts are two points clear at the top and they take on third-placed Birmingham Bears at Edgbaston - having lost to them by 18 runs when the two sides met at Trent Bridge on 11 June.
The Outlaws are unbeaten in eight games since that defeat - winning six, with two ending in ties.
Glamorgan v Sussex (start 17:30 BST)
Sussex have won the toss for this evening's early start and opted to bat first. They stick with the side beaten by Middlesex last night, and Glamorgan are also unchanged.
Both teams have Covid-related absentees - Marnus Labuschagne, Nick Selman and Michael Neser for Glamorgan, and Ollie Robinson, Delray Rawlins and Henry Crocombe among others for Sussex.
Glamorgan coach Matthew Maynard has urged his batsmen not to "tense up" and "try to force things", while opposite number James Kirtley believes they need to play "with a bit more instinct, a bit smarter".
Glamorgan: Carlson, Lloyd, Ingram, C Cooke, Root, Douthwaite, Weighell, Pearce, Taylor, Salter, Walker.
Sussex: Salt, Wright, Head, Bopara, Wiese, Ward, Thomason, Beer, Mills, Lenham, Claydon.
Glamorgan v Sussex Sharks, Cardiff (17:30 BST)
Durham v Leicestershire Foxes, Chester-le-Street (18:30)
Birmingham Bears v Notts Outlaws, Edgbaston 918:30)
Yorkshire Vikings v Lancashire Lightning, Headingley (18:30)
Somerset v Middlesex, Taunton (18:30)
Derbyshire Falcons v Worcestershire Rapids, Derby (19:00)
Hampshire Hawks v Gloucestershire, Ageas Bowl (19:00)
Kent Spitfires v Surrey, Canterbury (19:00)
Notts opened up a two-point lead at the top of North group by extending their unbeaten run to eight games with a six-wicket win over Leicestershire.
It was Alex Hales' 300th T20 game, but he only made 13 and it was left to the reliable Samit Patel, with an unbeaten 63, to guide the Outlaws home.
Image source, Rex FeaturesLancashire Lightning revived their challenge for a quarter-final place with a 34-run win over Worcestershire Rapids as Saqib Mahmood and Tom Hartley claimed four wickets each.
In South group, Devon Conway's unbeaten 81 led Somerset to an eight-wicket win over Gloucestershire and Essex Eagles cruised to victory by the same margin after bowling out Glamorgan for just 104.
Middlesex, meanwhile, proved too good for Sussex Sharks at Lord's, winning comfortably by 63 runs.
The T20 Blast began on 9 June and after three and a bit weeks of hectic, often thrilling, action, we take a short break after this evening's games.
The remaining group matches will be fitted in and around two rounds of County Championship fixtures, which begin on Sunday.
Before that we have eight games for you - including the latest meeting between perennial cross-Pennines rivals, Yorkshire and Lancashire.
Glamorgan and Sussex kick things off at 17:30. Welcome to our coverage.
Image source, Rex Features