Essex 211 for 3 beat Yorkshire 209 for 8 by seven wickets
An unbeaten century from Alastair Cook made sure Essex avenged their 10-wicket defeat by Yorkshire in the first Clydesdale Bank 40 League match of the season by gaining a comfortable seven-wicket victory in the return fixture at Headingley.
Yorkshire were guaranteed a home semi-final tie at Scarborough next Saturday regardless of the result and they have been drawn against Warwickshire, while Essex's win took them into the last four and their reward is a visit to Taunton to take on Somerset.
Chasing a target of 210 on a good batting pitch, Essex looked as if they were well capable of mirroring Yorkshire's achievement at Chelmsford as Mark Pettini and Cook piled up 161 together for the first wicket. But Pettini then hung out his bat at paceman Ben Sanderson and was caught behind by Gerard Brophy for 82 from 86 deliveries with six fours and two sixes, both of the big hits being scored at the expense of left-arm spinner David Wainwright.
Grant Flower was lbw to Wainwright in the following over to bring in Matt Walker, who smacked a breezy 19 before falling lbw to Pyrah just short of the finishing line. There was still sufficient time, however, for Cook to complete an unblemished century of 110 balls with ten fours and a six, the winning boundary then being thumped by Ryan ten Doeschate with 21 balls remaining.
A combination of determined bowling, spearheaded by David Masters, and superb wicketkeeping by James Foster restricted Yorkshire to a disappointing 209 for eight after they had been put in to bat. Masters, who bowled a fine opening spell, finished with figures of 4 for 41, including two wickets off consecutive balls, while Foster pulled off a sharp stumping and held on to three catches.
The Masters-Foster combination accounted for the first two dismissals, with skipper Andrew Gale out of his crease as Foster whipped off the bails while standing up to the stumps and Adam Lyth then neatly caught behind.
Once again Yorkshire's biggest contribution came from Jacques Rudolph, whose 59 from 68 balls with three fours took him to 755 runs in the competition - putting him two runs ahead of Darren Lehmann, who had held the White Rose record for the number of runs in a season.
There was also a finely struck half-century from Brophy, who helped Yorkshire recover from 41 for three through a fourth-wicket stand of 82 with Rudolph which ended when the left-handed opener aimed a cut at Chris Wright and was caught by Foster.
Brophy completed his 50 off 64 balls by cutting Ryan ten Doeschate for his third boundary but he was bowled off his pads by the next delivery before Masters chipped in with two in two, bowling Adil Rashid and pinning Pyrah lbw. Yorkshire were helped to a respectable total by Jonathan Bairstow whose two boundaries were both sixes, the first straight driven off Wright and the second achieved by flicking Masters off his legs.
Yorkshire skipper Gale said later: "Warwickshire have got a good record and are playing good cricket but we would have taken either them or Essex at Scarborough. "I was not particularly bothered who we would play in the semi-final, I was just glad to get through at Northampton last week.
"Ever since I put on a Yorkshire shirt as an 11-year-old I have dreamt of leading the side out at Lord's and to get there would mean the world to myself and all of the lads who will be giving 110 per cent to get to the final.
"I am not too worried about losing today - to win ten games out of 12 is a great effort. I thought 260-270 was a par score but losing three wickets in the first 10 overs put us under a lot of pressure and we didn't leave our bowlers enough to bowl at.
"We will certainly miss Tim Bresnan in the semi-final but I am hopeful that Ajmal Shahzad will be released by England and will be available to to play for us."