But when the dawn rises on Friday morning, a 2-2 result away from home will feel like a manageable outcome ahead of next week's return leg at Old Trafford.
By withstanding the loud racket made by Lyon's Bad Gones ultras on the Kop Virage Nord for so much of the game – between Lyon's two goals – Ruben Amorim surely has more evidence that his team has the capability to make it all the way to Bilbao.
The Reds had chances to score even more and looked composed on the ball for long stretches, and there were numerous bright spots all over the pitch – and from the substitute's bench – if you can overlook the frustration of that late leveller.