Tranmere will take a slender advantage into their Sky Bet League Two play-off semi-final second leg after goal-line technology helped them secure a 1-0 victory over 10-man Forest Green at Prenton Park.
Ollie Banks' 26th-minute piledriver cannoned off the underside of the crossbar and bounced back out but referee John Busby received notification that the ball had crossed the line and awarded the goal.
The visitors had Gavin Gunning sent off early on for kicking out at Jay Harris, but despite their numerical disadvantage, Mark Cooper's side defended resolutely in the second half to keep themselves in the tie.
The two sides know each other all too well having met in the 2017 Vanarama National League play-off final at Wembley, with the Gloucestershire side emerging victorious, and there was no love lost here as the sides matched each other tackle for tackle.
League Two's top goalscorer James Norwood fired wide early on, but just past the 15-minute mark Forest Green were reduced to 10 men when Harris fouled Gunning, who reacted by kicking out at the Tranmere midfielder, resulting in a straight red card.
With the numerical advantage, the Whites went on the attack and took the lead in the 26th minute as Banks unleashed an unstoppable swerving volley that made the crossbar shudder.
The midfielder became the first player ever to score at Prenton Park following the approval of goal-line technology.
Five minutes later, Norwood missed a golden opportunity to double the home team's advantage, blazing over at the far post.
Early in the second half, Christian Doidge wanted a penalty when he went to ground in the box under pressure from Tranmere defender Manny Monthe, but the referee waved his claims away.
The enraged Forest Green striker was then lucky to stay on the pitch, as moments later he stuck a sneaky elbow in the face of goalscorer Banks that went unspotted by the officials.
Unsurprisingly, Tranmere were showing the greater attacking intent. A cross from Liam Ridehalgh was headed wide by Norwood before Micky Mellon threw on attacking midfielders Jonny Smith and Harvey Gilmour in search of a second goal.
Substitute George Williams tried to buy the Green Devils a penalty but his claims fell on deaf ears.
Encouraged by the Kop, Monthe twice tried his luck from long range but only succeeded in firing over on both occasions.
Tranmere pressed hard to double their advantage in the closing stages but found their dogged opponents in no mood to give an inch.
The two sides will meet again on Monday night at the New Lawn, with the Birkenhead side holding the upper hand, but only just.
