|Vitality Blast quarter-final, The Spitfire Ground:|
|Kent 133-9 (20 overs): Billings 37; Parkinson 3-27, Lester 2-34|
|Lancashire 134-4 (18.4 overs) : Jennings 46, Vilas 30*, Clark 29*; Qayyum 2-17|
|Lancashire beat Kent by six wickets|
Lancashire reached T20 Blast Finals Day after a fine bowling display laid the platform for a nervy six-wicket victory over Kent at Canterbury.
Impressive young spinner Matt Parkinson took 3-27 as the hosts struggled to a modest 133-9 from their 20 overs.
Lancashire then lost England star Jos Buttler to a first-ball duck - just two days after his maiden Test century.
But international team-mate Keaton Jennings' 46 proved key as they made their target with eight balls left.
The England Test opener, batting at four for Lancashire, struck five fours, square cutting superbly, as he put behind him a string of low scores during the current series against India.
By contrast, Buttler failed to back up his superb innings on Tuesday with a meaningful contribution for his county, stumped by England white-ball specialist Sam Billings.
However, after Jennings had kept the visitors in contention, a 50-run fifth-wicket partnership between Dane Vilas (30 not out) and Jordan Clark (29 not out) dragged them across the line and on to a joint record seventh appearance at Finals Day.
The match had looked to be heading for a tighter conclusion before Clark smashed a six off the final ball of the 18th over and then successive fours during the penultimate over to complete victory.
Captain Billings had earlier top-scored with 37 for Kent, who had to recover from having Daniel Bell-Drummond run out without facing from the second ball of the match.
Lancashire, T20 winners in 2015, are the first side to book their place at Edgbaston on Saturday, 15 September.
In the other quarter-finals, Durham host Sussex at Chester-le-Street on Friday (18:30 BST), Worcestershire face Gloucestershire at New Road on Saturday (15:00 BST) and Somerset then meet holders Notts at Taunton on Sunday (15:00 BST).
Kent captain Sam Billings told BBC Radio Kent:
"A huge frustration to lose a home quarter-final. A sad end to our T20 campaign after looking the best side in the country.
"Our worst batting performance of the year. Batting first was the right decision but we batted terribly. We were 10 or 15 runs short.
"On a flat pitch, we'd back ourselves against anyone. But this wasn't really the pitch you want to prepare against Lancashire with their five spinning options.
"At least at Beckenham we know we're going to get a flat pitch. The only time we come unstuck is on snotheaps like this one."
Man of the match Matt Parkinson told BBC Radio Lancashire:
"You can see the effort and the class is there when we all perform. We hope we can take this momentum into Finals Day.
"As a unit, we bowled well, and to get three wickets in the powerplay eased our nerves a bit.
"It spun a bit more than we thought it would. That enabled to take more wickets and, from there, they had nowhere to go.
"We don't like to do things easy and it was a bit nervy, but credit to Keaton Jennings, Dane Vilas and Jordan Clark for seeing us home."