Kenedy repaid his loan fee in a single afternoon as he scored a double in Newcastle's priceless 3-0 Premier League win over Southampton.
The Chelsea midfielder struck after just 63 seconds and then again with 29 minutes gone to pave the way for a vital victory before Matt Ritchie completed the job 12 minutes into the second half.
With his side not playing again until Huddersfield head for St James' Park in three weeks, manager Rafael Benitez knew they could not afford to pass up the opportunity to claim three points towards their survival target, and his players did not disappoint in front of a crowd of 52,246.
They will embark on a four-day training camp in Spain next week knowing they need eight more points from as many games to hit the target of 40 points for survival.
By contrast, the Saints will head into their FA Cup quarterfinal at Wigan next weekend in real peril.
Newcastle could hardly have got off to a better start, taking the lead just seconds after the clock had ticked past the one-minute mark.
Jonjo Shelvey, who had been a doubt with a knee injury in the runup to the game, lofted the ball towards Kenedy, who took it on his chest and then span past marker Cedric Soares before scuffing a left-foot shot past keeper Alex McCarthy.
Southampton's response was creditable, with Mario Lemina and James Ward-Prowse leading the fight, and DeAndre Yedlin had to head clear a dangerous Cedric cross after the pair had combined nine minutes later.
However, Dwight Gayle spurned an opportunity with 25 minutes played when Mohamed Diame toe-poked the ball away from Lemina to put him in on goal, but McCarthy got down well to claim his left-foot strike.
Florian Lejeune had to hack away Nathan Redmond's goal-bound shot three minutes later but, from the resulting corner, Lemina missed his kick as he attempted an ambitious volley on the edge of the box and Ayoze Perez took full advantage.
The Spaniard raced away before laying the ball into Gayle's path, and he squared for Kenedy to tap home.
Saints boss Mauricio Pellegrino made a double change at the break when he withdrew Lemina and Dusan Tadic and replaced them with Josh Sims and Shane Long, but the Magpies went close within seven minutes of the restart when Perez glanced a header on to the roof of the net from Ritchie's corner.
Kenedy dragged a shot on the turn a yard wide two minutes later, but Ritchie was more accurate when he steered Shelvey's 57th-minute pass past the helpless McCarthy to make it 3-0.
Martin Dubravka made his first save of the game on the hour to keep out Guido Carrillo's near-post flick and Ryan Bertrand headed over from a corner five minutes later.
But although the Newcastle keeper also had to repel Sims' speculative effort 13 minutes from time, he emerged with a clean sheet intact.