Monaco currently lead Borussia Dortmund 2-0 at half time after young star Kylian Mbappe bundled the ball in from an offside position.
The referee and linesman waved away claims of the offside, with replays showing the French youngster had made his run a fraction too early.
Not only did Monaco get a slice of luck from the linesman, Mbappe knows nothing of the cross and it actually goes in off his midriff.
A Sven Bender goal gave Monaco a two-goal lead late into the first half.
That will now give the French side a massive boost, with an away goal already in the bag in this first leg.
The Ligue 1 have also been the stronger of the two sides in the first half, with Thomas Lemar and Kylian Mbappe given free reign.
With another 45 minutes to go, there is no doubt that this strong Borussia Dortmund side can still get back into the game.
Safe to say though, social media couldn’t quite believe the state of the goal which has downed the German’s in the first half.
— BT Sport Football (@btsportfootball) April 12, 2017
Lmfao lucky goal for Monaco
— Ra’id (@MesutsTouch) April 12, 2017
How offside was monaco's goal tho lol
— kae (@ImKorhan) April 12, 2017
Monaco goal was hella offside
— Jose Morales (@Jm8galaxy) April 12, 2017
— Deuce (@AZDEUCE2) April 12, 2017
Monaco fluke goal but that counter was deadly
— ArsenaLdn (@ArsenaLdn) April 12, 2017
— Luis Castillo (@luis_0224) April 12, 2017
Yikes. That Monaco player was offsides by a step when the ball was crossed. That goal should not have counted #UCL
— Alex (@halfwaycanadian) April 12, 2017
Monaco's goal was ridiculously lucky.
— Andrew Stewart (@andrewastewart) April 12, 2017
That was a messy Monaco goal but they'll take it
— Treble Nikki (@Treble_Nikki) April 12, 2017
Drama! Monaco miss a pen then score an offside goal! Mbappe bundles the ball in but it shouldn't have counted. Monaco don't care! #BVBASM
— bwin (@bwin) April 12, 2017