Wing Steff Evans scored a crucial try on his 100th regional appearance as Scarlets held on for victory in a closely-fought Guinness PRO14 clash.
Scrum-half Kieran Hardy also crossed in the 17-13 success in the rain at Parc y Scarlets, with Dan Jones adding seven points with the boot.
Cheetahs, who made it a real contest, were indebted to a try for scrum-half Tian Meyer. Tian Schoeman and Ruan Pienaar shared eight points with the boot.
Samoa’s Kieron Fonotia started at centre for Scarlets after returning from World Cup duty, Marc Jones got the nod at hooker, Lewis Rawlins started at lock and Ed Kennedy came into the back-row from the side that lost 46-7 at Edinburgh.
Cheetahs lost 24-22 at Connacht last week and were without centre Dries Swanepoel, given a three-match ban following his red card in that game.
Cheetahs opened the scoring with a 13th minute try from Meyer, who picked up a kick ahead by Janse van Rensburg to go over. Schoeman converted.
But Scarlets clawed their way back into the contest in the second quarter.
First Evans crossed from a line-out in the 22nd minute, with Dan Jones grabbing the conversion.
Three minutes before half-time Hardy exploited a gap down the blindside to go over after a turnover from Fonotia – and a break by Johnny McNicholl. Jones converted again for a 14-7 interval advantage.
It took the South African team only two minutes of the second half to get back into the contest with a Schoeman penalty.
And the visitors were boosted by the appearance of veteran replacement scrum-half Pienaar, who coolly kicked a penalty goal from a collapsed scrum.
It brought Cheetahs to within a point – but two minutes later Jones converted his second penalty after full-back Rhyno Smith had been penalised for holding on, on the floor.
Scarlets managed to maintain their advantage and it did not matter that Jones missed a penalty shot at goal with the final kick of the game.
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