Robert Earnshaw's late double saw Norwich snatch an unlikely win at Carrow Road as Nigel Worthington's side fought back from two goals down to stun QPR.
Gareth Ainsworth put the visitors ahead with his ninth goal of the season on the stroke of half-time completely against the run of play and Lee Cook made it 2-0 just after the hour-mark as the Londoners assumed control.
But Huckerby's 78th-minute strike set up a grandstand finish as the Canaries woke from their second-half torpor and Earnshaw made sure with two close-range finishes in the 85th and 90th minutes to complete an amazing turnaround.
Teenage striker Ryan Jarvis was handed his first start of the season for Norwich alongside Earnshaw and Paul Gallacher retained his place in goal due to Robert Green's ankle injury, while 17-year-old Spillane kept his place at right-back.
QPR caretaker-boss Gary Waddock made four enforced changes due to injury, with Georges Santos, Paul Furlong, Lomas and Marcus Bignot all returning to the starting line-up.
Spillane almost made an instant impact, his goalbound lob in the second minute keeping Paul Jones on his toes.
Earnshaw was next to test the QPR goalkeeper from 25 yards as the home side laid siege on the visitors' goal, while Ainsworth saw his drilled effort blocked by Gary Doherty at the other end.
Norwich continued to dominate in terms of possession but struggled to carve out further chances, with Earnshaw dragging his fierce 30-yard free-kick wide.
From another free-kick when Carl Robinson laid the ball off to Darren Huckerby 20 yards out, the latter sent his shot fizzing over the crossbar.
But Norwich were made to pay by Ainsworth who steered home Lomas' cross in the 45th minute.
Earnshaw volleyed wide straight after the restart and Huckerby's stinging volley was well saved by Jones, but QPR almost doubled their advantage when Marc Nygaard's header from Cook's corner was brilliantly parried by Gallacher and Furlong's follow-up shot was blocked by Andy Hughes.
Furlong then forced Gallacher into another fine save with a shot from 12 yards before the veteran striker headed over the crossbar, but there was no denying the visitors a second in the 61st minute.
The ball broke kindly for Cook on the edge of the penalty area and the 23-year-old drilled home his fourth goal of the season, low beyond Gallacher into the bottom corner.
Huckerby then set up a grandstand finish when he thumped home Andy Hughes' cross from close range with 12 minutes left and a double substitution - Jonatan Johansson and Ian Henderson on for Jarvis and Hughes - gave the Canaries fresh impetus.
Johansson's cross was volleyed home by Earnshaw from inside the six-yard box in the 85th minute and a 24,126-crowd raised the roof when the pint-sized striker blasted home the winner from Paul McVeigh's knockdown in the final minute.
Teams
Norwich: Gallacher, Spillane (McVeigh 45), Shackell, Doherty,Drury, Hughes (Henderson 79), Etuhu, Robinson, Huckerby,Earnshaw, Ryan Jarvis (Johansson 78).
Subs Not Used: Lewis, Charlton.
Booked: Etuhu.
Goals: Huckerby 78, Earnshaw 85, 90.
QPR: Jones, Bignot, Shittu, Santos, Milanese, Ainsworth,Bailey, Lomas, Cook, Furlong, Nygaard.
Subs Not Used: Cole, Bircham, Kus, Munday, Howell.
Booked: Santos, Bailey.
Goals: Ainsworth 45, Cook 61.
Att: 24,126
Ref: B Curson (Leicestershire).