Somerset & Birmingham Bears win to ensure they will end top of their respective groups
Bears beat Notts despite Shaheen Shah Afridi's four wickets in first over of Bears' run chase
Sussex's Ravi Bopara and Derbyshire's Tom Wood score centuries in victories for their sides
Lancashire v Yorkshire abandoned without a ball bowled
Worcestershire v Durham ends in tie on DLS after early end because of rain
Worcs v Durham 13-1 (2 overs)
Adam Finch wants Durham batter Graham Clark lbw second ball of the second over but it was always going wide and the umpire is not fooled.
Clark ends the over with a wonderful shot over mid-off for four. Touche, Mr Finch, he says.
Worcs v Durham 3-1 (0.4 overs)
After losing the toss and being put in, it's not the start Durham wanted.
Skipper Alex Lees doesn't exactly lead from the front on this occasion, handing Usama Mir a gift of a catch at mid-on from just the fourth ball of the match.
Similar to the North Group, one South Group team has already secured a quarter-final berth - leaders Somerset, who have also secured home advantage in the last eight.
Tonight, they visit Surrey in a top-two tussle with the hosts knowing victory will ensure their own progression.
Next come three sides all tied on 14 points - reigning champions Hampshire Hawks, Kent and Essex - who are all at home tonight.
The four qualifiers should come from those five counties, with Glamorgan and Sussex needing two wins and big favours elsewhere, while Gloucestershire and Middlesex are already eliminated.
Birmingham Bears have already qualified for the quarter-finals but victory at Notts Outlaws tonight would ensure a home match in the last eight.
That would give them home advantage for the rest of the competition - providing they make it through to Finals Day, of course, which is being held at Edgbaston.
But the remaining three quarter-final places are all up for grabs - Worcestershire, Lancashire and Notts are the sides currently in the driving seat and all three are at home tonight.
The only side mathematically unable to qualify is bottom team Leicestershire.
Worcestershire Rapids v Durham (17:30 BST)
Image source, Getty ImagesOur early start tonight comes at New Road where Worcestershire can take a huge step towards qualification for the quarter-finals by beating Durham.
The Rapids have won four and lost two of their six Blast home games thus far this year.
Durham, meanwhile, have to win to have any chance of progression after the rain frustrated them at home to Yorkshire last week.
The match features two of the five most prolific wicket-takers in this year's competition - Worcestershire's Pat Brown and Durham's Nathan Sowter have 21 apiece.
18:30 BST unless stated
North Group:
South Group:
Image source, Rex FeaturesWhile two of the international game's oldest adversaries are locked in battle in the second Ashes Test at Lord's, two old rivals of English county cricket meet in a potentially pivotal T20 Blast group match at Emirates Old Trafford.
A victory for hosts Lancashire will send them a step closer to the quarter-finals.
It is very much win or bust for Yorkshire, though. They must win this, their final group game, to stand a chance of reaching the last eight. It was they who came out on top by 15 runs in the reverse fixture on 1 June.
That one gets under way at 19:00 and it's one of eight matches you can follow with our text and radio coverage on this page.