Adelaide Strikers 202 for 4 (Lynn 69*, Kellepotha 2-32) beat Melbourne Renegades 182 for 6 (Harper 63, Agar 2-26, Short 2-26) by 20 runs
Strikers claimed early wickets to derail Renegades' chase and leapfrog to third on the BBL ladder with their fifth win of the season.
Chris Lynn's hot form continues
After a sedate start with his new team, Lynn has been on a roll before he heads to the new cashed up T20 league in the UAE.
As has been his approach during a bounce-back season, Lynn started watchfully after Strikers lost openers Matthew Short and Ryan Gibson in the seventh over.
He scored 25 off his first 18 balls before launching a muscular six down the ground off seamer Tom Rogers. It sparked Lynn, who combined with Colin de Grandhomme in a blistering 78-run partnership to power Strikers again past 200.
De Grandhomme's 16-ball 32 was marked by three straight sixes off quick Kane Richardson, who moved gingerly at times and was uncharacteristically expensive with 1 for 62 off four overs.
Lynn finished the innings superbly with an assault on Richardson to underline his red-hot form. But the power hitting amid steamy conditions took its toll on Lynn, who was off the field in Renegades' innings due to fatigue.
Ruwantha Kellepotha delivers in BBL debut
There was intrigue over how a new-look Renegades attack would overcome the losses of spin duo Mujeeb Ur Rahman and Akeal Hosein, who have headed to the UAE.
Englishman Critchley could do little to stem the tide with a six by Gibson off his first ball amid a 17-run over. In his BBL debut, Kellepotha fared better by hitting a length and stemming the rampaging run rate.
He broke the 63-run opening partnership by removing Gibson caught at backward point then was perhaps fortunate to dismiss Short with a half-tracker.
The Sri Lankan's figures took a slight beating from Lynn with his last ball of his allotted overs hit for six.
But he was still Renegades' standout bowler to cap a rise for the 31-year-old journeyman, who earlier in the domestic season earned a shock Sheffield Shield call-up for Victoria after strong performances in Melbourne club cricket.
Kellepotha had played 20 first-class games in Sri Lanka between 2011-2013 before his unexpected career revival and he looms as an X-factor for Renegades after an encouraging debut.
Strikers overcome Colin de Grandhomme's injury
Strikers had a new-look attack after talisman Rashid Khan departed for South Africa's new T20 league. They did not select leading wicket-taker Henry Thornton, while veteran quick Peter Siddle remains sidelined with a back injury.
They suffered a blow when de Grandhomme was unable to take the field after injuring a hamstring while batting. Strikers missed his ability to bowl slower deliveries - particularly invaluable on the flat Adelaide surface.
But Strikers' attack generally bowled with discipline to overcome de Grandhomme's absence with former Australia T20 legspinner Cameron Boyce mustering his experience in a solid season debut.
Short and Wes Agar claimed two wickets apiece to ensure Strikers were never seriously threatened.
Sam Harper continues strong comeback
In a much-needed tonic for Renegades, wicketkeeper-batter Sam Harper has recaptured his belligerent best after scoring just six runs in four innings, including three ducks.
While Renegades' top order struggled, Harper looked a class above and made his move in the middle overs. He smashed 19 runs in a five-ball purple patch and notched up a second straight half-century.
But his dismissal in the 13th over seemingly snuffed out Renegades' challenge before a late cameo from Will Sutherland provided a flicker of hope.
Sutherland couldn't conjure something miraculous, but his 31 off 14 balls only further fuels a belief that he should move a couple of spots higher than his current No.7 position.
Tristan Lavalette is a journalist based in Perth