Manchester United took the lead through Joshua Zirkzee goal, but were held to a 1-1 draw at Real Sociedad  in the first leg of their Europa League last-16 tie.
United had the only real chance of the first half against Sociedad when Bruno Fernandes had a goalbound shot blocked and Zirkzee’s follow-up effort was saved.
But a fortuitous penalty, converted by Mikel Oyarzabal, midway through the second period brought the hosts back level in that game.
As the hosts grew in confidence after the Equaliser, Mendez forced United keeper Andre Onana into a fine save and substitute Orri Oskarsson put a close-range effort wide but United hung on to remain the only unbeaten side in the competition this season.
But the tie remains finely balanced in a 1-1 draw ahead of the return leg at Old Trafford in seven days’ time.