The 19-year old started in a new-look
A largely inexperienced
Wales soon went on to extend their lead through a free-kick from Cardiff's Joe Jacobson, before Manchester City striker Ched Evans grabbed a brace either side of the break to complete the rout.
The young Dragons' electrifying display left under-21 boss, Brian Flynn swooning: “I really couldn't have asked for more,” said the Dragons coach, speaking to Sporting Life after his sides thumping victory.
"This was a completely new squad in effect, and they were excellent.
"There is some talented youngsters among this group and if they keep improving and stick together there is every chance that several of them will make it in the game.
The Welsh under-21 side has provided the senior side with rich pickings from the country's top youngsters, with players constantly being promoted to their senior squad as recently as this season.
Now, Flynn is confident this current crop of youngsters can emulate their predecessor's former glories: "We have been able to send the likes of Gareth Bale, Lewin Nyatanga, David Cotterill and Joe Ledley up to the seniors from the previous Under-21 group, and there are a few more here who have that potential.
"I recall our last game against
"But the improvement shown since then now sees us with a very strong group of lads.
Warlow is yet to make his first team bow at Sincil Bank, despite being a virtual ever-present in the club's reserve and youth sides.
Wales U21: Hennessey, Gunter, Jacobson, Edwards, Rhys Williams, Mike Williams, Grubb, Collins, Vokes, Evans, Warlow.
Subs: Owain Fon Williams, Bradley, Flynn, Blake, Davies, James, Jones.