Sussex 159 for 6 beat Kent 144 for 8 by 15 runs
England's deposed Twenty20 wicket-keeper Matt Prior blasted a match-winning 89 off 59 balls to steer Sussex to a 15-run Friends Life t20 win over South Group rivals Kent in Canterbury.
The Sharks win, masterminded by Prior's knock of nine fours and a brace of sixes, severely dented Spitfires' hopes of reaching the quarter finals while bolstering the Sharks chances of qualifying for the knock-out stages.
Prior featured in stand worth 47 with Ed Joyce and then 69 in 8.1 overs with Ben Brown (20) after visiting skipper Michael Yardy won the toss and elected to bat first in front of a St Lawrence crowd of 3,500.
The hard-hitting right-hander might have gone with his score on 34 and then on 61 after miscuing on drives against the bowling of Darren Stevens, yet both times the fielder failed to make the catch after losing the flight of the ball in the setting sun.
Other than Brown, no-one gave Prior the support he deserved and wickets continued to tumble at the other end with Wahab Riaz bagging three for 22, which included the scalp of Lou Vincent for six to a stunning catch one-handed and high to his right by another former England keeper, Geraint Jones.
Charl Langeveldt chipped in with two for 32 including Prior's wicket to a miscued catch at backward point by home skipper Rob Key and Kent went into the interval seemingly delighted to have restricted the Sharks to 159 for 6.
Chasing a victory target at the rate of eight an over, Kent lost Joe Denly in the second over leg before after missing an attempted reverse sweep against off-spinner Ollie Rayner.
Key heaved across the line of a good length ball from Umar Gul to have his middle stump pegged back then Azhar Mahmood dawdled a single to backward square only to be run out by Gul's direct hit that made it 44 for 3.
With rain starting to fall Kent's mood darkened when Sam Northeast (seven) chipped tamely to mid-on then Alex Blake haplessly steered a simple catch to backward point. Spitfires' victory hopes now lay squarely on the shoulders of experienced seventh-wicket partners Stevens and Jones.
Stevens flailed his way to a 36-ball 50 with four fours and two sixes but with his score on six Jones sliced a drive against Gul to Brown at deep cover and at 118 for six hope hopes were as good as dashed.
In his next over Gul yorked Riaz to finish with three for 26, then rookie Sam Billings spooned a leading edge catch to cover off the bowling of Nash leaving Stevens and James Tredwell to score 30 off the remaining two overs - a task that proved well beyond them.