|Vitality Blast quarter-final, Emirates Riverside:|
|Lancashire 159-5 (20 overs): Davies 80*; Bopara 2-28|
|Essex 165-4 (19.2 overs): Ten Doeschate 45*, Bopara 39*; Mahmood 1-10|
|Essex beat Lancashire by six wickets|
Ravi Bopara hit four sixes off his last six balls as Essex beat Lancashire to reach the T20 Blast semi-finals.
After Cameron Delport's rapid 44, Essex lost wickets in consecutive deliveries.
But Bopara (39 not out) and Ryan ten Doeschate (45 not out) put on 60 in five overs to guide their side home by six wickets with four balls remaining.
Alex Davies made a composed unbeaten 80 and shared 89 in 13 overs with captain Dane Vilas (41), who hit the only six of the Lancashire innings of 159-5.
The penultimate over proved pivotal as Lancashire gambled on the leg-spin of Liam Livingstone and he went for 22, including three sixes.
Former England batsman Bopara, 34, has now made 156 runs without being dismissed in his last three innings in the competition and his controlled power ensured his side became the first team through to Finals Day at Edgbaston on 21 September.
Lancashire lost only two matches in topping the North Group, but made an uncertain start after being asked to bat when play began in bright sunshine following heavy afternoon rain in Chester-le-Street, staging the fixture because of the Test match taking place at Lancashire's Old Trafford home.
The six powerplay overs saw the Red Rose county record 47-3 with Australian power-hitter Glenn Maxwell among the dismissals, trapped lbw having struck three boundaries in an over.
They were indebted to former England Under-19 batsman Davies, who played a mature innings to keep the scoreboard moving. He then displayed his improvisational skills to dispatch Aaron Beard for back-to-back boundaries over the wicketkeeper's head with pre-meditated ramp shots in the penultimate over.
Essex were 14-1 after 3.1 overs when the players were taken off for rain and when play resumed, the burly South African left-hander Delport, who blasted 129 from 49 balls against Surrey in July, struck three boundaries in a James Faulkner over to put the visitors ahead of the required rate.
But with the rain falling again, Delport holed out to long-on and then Adam Wheater was run out next ball by a direct hit from the boundary going for a second run.
A superb low diving catch at long-on by Faulkner dismissed Dan Lawrence in the 15th over with 55 still needed, but the experienced Ten Doeschate and Bopara left their team with 23 to win from 12 balls, Steven Croft parrying a Bopara lofted drive over the boundary for six.
After successive sixes off Livingstone, man-of-the-match Bopara, who also dismissed Maxwell in his 2-28, won the match with another maximum off Matt Parkinson as Essex secured a remarkable victory.