Lancashire 140 for 8 (Croft 41, Vilas 40, Garton 3-28) beat Sussex 95 (Wright 36, Livingstone 4-23, Parkinson 3-9) by 45 runs
Lancashire's spinners were too good for Sussex on a slow wicket at Hove, returning combined figures of 8 for 50 in 9.2 overs to seal their spot at Finals Day for the eighth time in their history.
After struggling their way to 140 for 8 thanks to contributions from Steven Croft and Dane Vilas, Lancashire turned to their three-pronged slow-bowling attack comprising Tom Hartley, Liam Livingstone and Matt Parkinson to send Sussex's run-chase into disarray.
Sussex were 34 for 2 after the Powerplay - exactly the score Lancashire had reached after six overs - when Vilas turned to spin, and needed to tick over on a hybrid pitch. Those surfaces are usually renowned for the bounce and carry they offer, but this strip proved sticky and on the slower side. Sussex struggled to rotate, failing to score from 49 of the 104 balls they faced, and crumbled to 95 all out to end Jason Gillespie's reign as head coach with a heavy defeat.
Sussex on top early
Lancashire had flown out of the blocks batting first this season, scoring at nine an over in the Powerplay coming into this game, and when Livingstone belted Ollie Robinson for sixes in the second and fourth overs, it looked like that would continue. But when he freed his arms in the hopes of another towering blow over midwicket, he looked round to see his leg stump pegged back.
That brought Keaton Jennings to the crease, tasked with anchoring the innings at No. 3. He clipped Robinson off his pads for four through wide long-on, but then miscued when rushed for pace by George Garton, offering a steepler to David Wiese at mid-on in the ring. With Croft struggling for timing against Tymal Mills' changes of pace and Sussex electric in the infield, Lancashire's Powerplay total was their second-lowest of the season.
Vilas' lone hand
Sussex's penchant for allrounders meant that they came into this game with eight bowling options, and Wright was happy to chop and change as he saw fit. He opted for a number of one-over spells through the middle overs in order to stop Lancashire finding their rhythm, exemplified by Davies picking out deep backward square leg as he swept a Delray Rawlins full toss, immediately after Ravi Bopara had interrupted the diet of left-arm spin.
With 22 runs to his name off 30 balls at the end of the 13th over, Croft recognised he had to accelerate, and promptly deposited Rawlins for two sixes. Wright brought Garton back, chasing a breakthrough, and saw his second ball pulled over long leg for six more, but one ball later, he was well caught by Robinson on the rope looking to repeat the trick, prompting whoops and cheers from the balconies of the flats on Palmeira Avenue.
But the variety offered by Sussex's death bowlers could not prevent Vilas from hitting a crucial cameo of 40 off 28 balls, which included a wristy skewed six over wide third man and a slash over the vacant slips for four. If Vilas rode his luck, he also rotated brilliantly: he absorbed only four dot balls on a pitch where ticking over was the order of the day.
Lancashire win the match-ups
All three of Lancashire's main spinners have significantly better records against right-handers than left-handers, and Rawlins, the only leftie in Sussex's top six, has a reputation as a destructive player of spin. With that in mind, it was vital for Vilas that he managed to get Rawlins out early which would expose Sussex's right-handers to the ball turning away from them.
Luke Wood's opening over saw both Wright and Phil Salt hit boundaries, but when a fired-up Saqib Mahmood dismissed Salt with his first ball, miscuing a pull to mid-on, it meant an early entry for Rawlins at No. 3. He played skittishly, taking on the short ball without finding the middle and failing to hit his characteristic early boundary to settle his nerves.
Lancashire rallied in the field, barking encouragement and sensing an opportunity as Wood steamed in for his third over with the new ball; he pegged back Rawlins' off stump with a yorker, and wheeled away in delight, knowing full well that he had set things up perfectly for a middle-over spin fest.
Spin seals it
Sure enough, Vilas turned to Hartley and Parkinson as soon as the fielding restrictions were lifted, and Hartley - a tall left-arm spinner in his breakthrough season - accounted for Bopara, who was trapped lbw on the sweep. With Sussex finding it hard to rotate the strike with Lancashire in tight to save singles, David Wiese broke the shackles when Livingstone arrived to bowl his liquorice allsorts, nailing a slog-sweep for six into a van.
But two balls later he skied a catch to Rob Jones, running in from long-on, and Livingstone got the key wicket of Wright in similar fashion, as his loose drive picked out long-off. At 77 for 5 at the start of the 15th over, Sussex had no choice but to attack, and the result was three wickets in four balls for Parkinson who proved too good for the lower order. Mills belted a sublime straight six over long-on with the game effectively over, and became the only Sussex batsman other than Wright to reach double figures before he was stumped to give Livingstone his fourth and seal Lancashire's semi-final spot.
Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98