It had all started so promisingly for Dundee United’s young guns but a Kyle Lafferty hat-trick proved, sometimes, there is no substitute for experience.
The Kilmarnock hitman bagged a 10-minute first-half treble to down the Tangerines’ tykes and send Tommy Wright’s men closer to Premiership safety.
With bottom side Hamilton losing to the Lanarkshire derby to Motherwell earlier in the evening, the Ayrshire men needed no bigger carrot.
Three points moved them five clear of Accies with three games to go and lifted them out of the relegation play-off spot.
St Mirren seeing off Ross County meant the Staggies replaced Killie in 11th, while United dropped to eighth spot headed into a big weekend for the club’s aspirations.
With a view to Sunday’s Scottish Cup quarter-final at Aberdeen, Micky Mellon fielded an experimental line-up showing seven changes.
Youngsters Kerr Smith (16) and Florent Hoti (20) made full debuts, while there were also returns to the starting XI for Mark Connolly, who skippered the side, Luke Bolton, Ian Harkes, Jeando Fuchs and Louis Appere.
Mark Reynolds, Ryan Edwards, Calum Butcher, Peter Pawlett, Nicky Clark, Lawrence Shankland and Marc McNulty all dropped out from Friday night’s 1-0 cup win at Forfar.
Young Terrors start brightly against relegation-threatened Killie
Just two minutes in, United looked to get at Killie down the right flank as the players basked in the Wednesday evening sun at Rugby Park.
Appere’s impressive hold-up work brought Harkes into play as the American sprayed it out wide for an overlapping Liam Smith.
His flashed delivery across the six-yard box was begging to be turned home but there were no takers for the inviting cross.
Lafferty won his side a corner soon after as he saw his speculative effort charged down. However, Killie’s training ground routine from the resultant kick bore no fruit.
Connolly’s head met Hoti’s corner on 12 minutes but the ball looped comfortably into the arms of home keeper Colin Doyle.
At the other end, Connolly was in the way this time, making a crucial block from Chris Burke’s goal-bound daisy-cutter.
Burke’s deep delivery from a free-kick on 18 minutes caused confusion among the United backline as stand-in stopper Deniz fumbled his attempted catch.
However, Kerr Smith was the calm among the chaos, showing composure beyond his years to sweep up the loose ball.
Ross Millen was next to throw the cat among the pigeons as his whipped delivery went a-begging with Lafferty lurking.
The Terrors were working hard to regain a foothold, with Mellon’s favourite touchline cry to “pinch” the pitch prompting a tornado of tangerine to swirl around in search of possession and chances.
Captain for the night Connolly performed some heroics at the back to keep the score level approaching the half-hour mark.
United will have hoped Appere’s effort from distance would signal a turn in the tide back in their favour as they won a corner-kick.
Three goals in 10 minutes all but seals the deal for Killie
However, the reality was very different indeed.
A passionate Mellon was engaging in a war of words with fourth official Gavin Duncan as a Lafferty header trundled wide of Deniz’s left-hand post.
Just after the half-hour mark, however, Northern Irish international Lafferty made no mistake from Millen’s cross as he crashed home a towering header beyond Deniz from a matter of yards out.
Three minutes later, Lafferty made it two for him and Kilmarnock on the night, once again connecting with Millen’s cross but this time calmly stroking home the cutback from the centre of the goal.
When it appeared easier to just clear the ball, United tried to play themselves out of trouble as Fuchs brought down Burke in the box as he tied himself in knots.
Referee Alan Muir pointed to the spot as Lafferty stepped up and sent Deniz the wrong way from 12 yards to bag his hat-trick and Killie’s third on 43 minutes.
Shortly after the restart, Mitch Pinnock forced Deniz into a low, stooping save as the hosts looked to put the contest beyond all doubt.
The Terrors, however, were far more resolute in the second period, holding off an energised and highly-motivated Killie side for the large part.
On the hour mark, Mellon handed another debut to young Archie Meekison (18) as the midfielder replaced fellow-kid Hoti.
This was all happening while Deniz was down in a heap in the six-yard box after hurting himself in controlling Liam Smith’s rifled back pass.
United’s goalie coach, 43-year-old Neil Alexander was preparing to enter the fray, but, no doubt much to the former Rangers and Scotland keeper’s relief, his services weren’t required.
Deniz carried on and United continued to look for away back into the contest. Adrian Sporle fired over from distance on 64 minutes, while Appere continued to influence proceedings in the No 9 role.
Meekison let loose from 30 yards and wasn’t a million miles away as his shot arrowed narrowly over Doyle’s crossbar.
On 72 minutes, Luke Bolton saw his near-post effort well-saved Doyle. Shortly after, Harkes scooped over from 20 yards as the Tannadice men looked far sharper.
Deniz was right behind Rory McKenzie’s bouncing strike two minutes after as Killie came back into proceedings.
With 10 minutes remaining, Fuchs recovered well to block substitute Nicke Kabamba’s effort from the edge of the area.
Heading ever closer to the full-time whistle, Sporle saw his breakaway effort smothered by Doyle before Appere and Sporle again compounded to miss with the goal gaping.
Alan Power volleyed over from nearly 35 yards before Doyle pulled off a top save from Harkes’ curled effort.
Killie held on for an impressive win that lifts them out of relegation places as United’s focus turns to securing themselves a Hampden berth.
Dundee United (4-2-3-1): Deniz (GK); L Smith, K Smith, Connolly, Robson; Harkes, Fuchs; Bolton, Hoti (Meekison 60), Sporle; Appere.
Subs not used: Alexander (GK), Reynolds, McNulty, Clark, Edwards, Butcher, Shankland and Davidson.
Kilmarnock (4-2-3-1): Doyle; Millen, Broadfoot, Ibsen Rossi, Haunstrup; Power, Dicker (C); Burke (Tshibola 76), McKenzie, Pinnock; Lafferty (Kabamba 76).
Subs not used: Rogers (GK), McGowan, Medley, Waters, Mulumbu, Kiltie and Oakley.
Referee: Alan Muir.