Essex 189 for 6 (Delport 64) beat Kent 179 (Crawley 89, Porter 3-28) by 10 runs

Essex snuck through to the quarter-finals of the Vitality Blast after stealing an improbable win against Kent, who suffered a third batting implosion in a run chase in as many games.

The PA announcer at Chelmsford had promised radio silence regarding results from elsewhere, and with Essex needing the hitherto hapless Glamorgan to secure a first win of their campaign against Hampshire, it seemed unlikely that even a convincing win would have been enough.

But after Jamie Porter bowled Mitchell Claydon to seal victory, the news that Hampshire needed 36 from their final seven balls to get through brought the loudest cheer of the night, as the sold-out crowd spilled out into the streets of Chelmsford to continue the celebrations, with a quarter-final at Chester-le-Street against Lancashire to look forward to.

"We've snuck in through the back door," admitted Ravi Bopara, who starred with both bat and ball. "We had a chance mathematically [at the start of the week], but if we're being brutally honest there was no chance, really. In our minds, we were like - it's going to take ridiculous results to go our way. The fact that it happened is just unreal."

He was right, too. Essex's first ten fixtures had brought just two wins, with three abandonments and a no-result robbing them of the chance to go on a winning run. But with the pressure off, they have flourished, and find themselves in the quarter-finals for the first time since 2016.

"I think guys just went 'look, it doesn't matter now, it doesn't matter now, let's just go out there and express ourselves, and go for it'," Bopara said. "It's come off. Some of those games were close - it's amazing you can qualify by a width of a hair."

It was unthinkable at the halfway stage in this competition to think that Kent might not make it through to the knockouts. They had won six of their first seven games, and were good value for it; with Sam Billings waiting to make his return from injury, and their star-studded bowling attack running the show, they were the competition's form team.

But their final seven games have brought two abandonments, and five defeats. The past three have been particularly painful: against Surrey, they needed 18 off 12 balls with nine wickets in hand and threw it away; on Thursday, they needed 12 off nine with Alex Blake and Faf du Plessis well set, and conspired to stuff up another chase.

If this loss was just as catastrophic, so too was it the one with the most meaning attached. While the rest of the five teams bunched either side of the qualification places reached for the abacus, trying to work out margins of victory and net run-rate equations, Kent's equation was simple: win and qualify, lose and bow out.

And while it was cruel on Zak Crawley, who played brilliantly for his 89, that his dismissal should precipitate Kent's downfall, his decision to try to hit Adam Zampa for a third six of the over - having played-and-missed at the following ball on both previous occasions - was a poor one with 40 needed from 25.

He set in motion a dramatic collapse of 7 for 29. Bopara, who had a brilliant night with the ball, had Heino Kuhn bowled slogging across the line, and then Ollie Robinson held at long-off in the same over, before Mohammad Amir yorked Alex Blake and Imran Qayyum with successive deliveries.

That left 16 to win off the final over, with Porter entrusted with the ball. Any nerves were soon settled as he sent Hardus Viljoen's stumps flying with his first ball, then performing the same trick to remove Claydon with his last.

Essex's score of 189 for 6 looked a promising one at the halfway point, but it came on the highest-scoring ground in the competition to date.

Their total owed much to Cameron Delport's entertaining 64, which got Essex off to a bright start after winning the toss. He struck five fours and as many sixes in his 29-ball innings, and continued to attack as those at the far end fell away.

And after his unbeaten 70 off 35 balls on Thursday night helped see off Surrey, Bopara was again the hero. He was left out for two games earlier in the tournament after "tough" conversations regarding his batting position, and remains frustrated about coming in as low as No. 6, but has channelled that into three vital innings in their past three games.

In the chase, Crawley was dominant from the outset, and displayed the array of primarily orthodox shots that have seen him talked about so highly as a future England Test opener.

That Kent's campaign fell away so badly owed plenty to the loss of their overseas players Mohammad Nabi and Adam Milne, meaning that du Plessis - who only left South Africa on Thursday morning due to a visa hold-up - was floated in for what proved to be their final two games.

And he was involved in an intriguing subplot after starting with two exquisite drives over long-off for six then four. Zampa's past three balls to du Plessis in T20 cricket had brought two wickets, though in the colours of Guyana and St Kitts rather than Essex and Kent, and this encounter proved little different; after knocking four singles, du Plessis took the legspinner on, and could only chip to short cover.

Crawley then built steadily with Billings and then Kuhn, but after he found Harmer on the boundary, things fell to pieces.

Kent were left scratching their heads as to how things had gone this wrong; Essex's attempts to seal a Championship/Blast double continue.

Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98