Newcastle Falcons took a pair of bonus points and were within a whisker of a winner in Friday's Kings of the North visit of Leicester Tigers.
Chris Harris' late try got the home side to within two points, and the replacement looked to have clinched the result with a scything break in the final seconds.
Referee Andrew Small judged the Cumbrian to have been held up over the try line with the very last play of a dramatic game, and with no video referee available that was that.
The Falcons kept their composure despite an early tide of points going against them, battling from 22-0 down to reduce the half-time arrears to eight points.
On a night when the home side opted to turn down kicks at goal Leicester took the opposite path, Freddie Burns opening the scoring on three minutes with a simple chip over from 20 metres.
American No 8 Todd Clever kept the Tigers' defence honest with a series of open-field bursts, the debutant offloading well and running some sensational support lines.
Another Newcastle new-boy, Mouritz Botha, was towering at line-out time and even popped up with a clear line-break from first receiver, but it was the visitors who grabbed the first try of the night.
Hooker Harry Thacker was the scorer, making the most of a clear break to beat the last man and score.
Burns added the extras, Leicester's ruthless use of counter-attack ball rewarded on 21 minutes when former Fiji centre Seremaia Bai scored in the right corner.
His side's lead increased further before the half hour as Riccardo Brugnara barged a path to the try line from centimetres out, a series of pick-and-go bursts allowing the prop a sniff of the whitewash.
But the Falcons ended the half with by far their best spell, Craig Willis beating the defensive line with footwork and pace on a number of occasions.
Mayhew and Clever both broke the line and got offloads away, the latter scoring a well-deserved try when his charge-down of a Tigers clearance kick saw him grounding the loose ball in the left corner.
It got even better before half time, Dan Marshall's 50-metre burst and Mayhew's support putting the hosts in prime field position.
Leicester were reduced to 14 men when Adam Thompstone was sin-binned for a deliberate knock-on as Willis attempted to put Marshall in for a try, but the subsequent five-metre scrum saw a dominant Newcastle eight driving over for a converted penalty try.
That reduced the half-time deficit to 22-14, and there was only a single point in it when Ruki Tipuna scored at the start of the second half.
The Kiwi Scrum Half showed amazing acceleration from the base as he scurried in for a score in the right corner, Willis converting impressively from out wide.
Harris tested the visitors' defence with a clear run from an inside pop, but Burns added daylight between the sides when he scored from a two-on-one down the left.
Tommy Bell's penalty took the gap out to nine, Newcastle finishing the game with a youthful back line as Brett Connon, Tom Penny and Ed Coulson entered the fray.
Penny stripped Peter Betham in a tackle and almost had an interception try from inside his own half, but there was still time for late drama.
Leicester were reduced to 14 men for the final 10 minutes when Mike Williams was sin-binned under forward pressure, Newcastle making it count when Dan Temm's diagonal run put Harris away for a try in the right corner.
Trailing by two going into the final five minutes, it was the home side who enjoyed territory and possession during a gripping climax.
Ruki Tipuna felt he had scored only to be pulled back for a knock-on, and when Harris crossed the try line with the final play it looked to many inside the stadium that he grounded the ball.
Referee Small deemed it to have been held up, and there was no time to restart what had been a frenetic game.
Newcastle Falcons M Watson, D Marshall, A Powell, J Tali, Z Kibirige, C Willis, R Tipuna; R Vickers, S Lawson, A Rogers, M Botha, S MacLeod, R Mayhew, W Welch (captain), T Clever. Replacements: G McGuigan, B Harris, A Foster, C Green, D Temm, C Chick, R Dawson, B Connon, C Harris, T Penny, E Coulson.
Falcons scorers – Tries: T Clever, Penalty try, R Tipuna, C Harris. Conversions: C Willis 3, B Connon.
Leicester Tigers M Tait (captain), A Thompstone, P Betham, S Bai, G Catchpole, F Burns, S Harrison; R Brugnara, H Thacker, F Balmain, M Fitzgerald, S de Chaves, M Williams, T Croft, L McCaffrey. Replacements: J Farnworth, G Bateman, T Pasquali, J Maksymiw, L Pearce, B White, J Roberts, T Bell, W Evans, C Loamanu, G Tressider, G Worth, P Odogwu.
Sin-bin: A Thompstone (39), M Williams (70).
Leicester scorers – Tries: H Thacker, S Bai, R Brugnara, F Burns. Conversions: F Burns 2. Penalties: F Burns, T Bell.
Referee: A Small. Attendance: 2,530.