The former Tottenham striker made the accusation during the Champions League game between United and CSKA Moscow on Tuesday evening.
In the 73rd minute, England international winger Young went down in hope of earning a penalty.
Lineker was following the match at Old Trafford, and he was not impressed with the antics of his compatriot.
Ashley Young doing what Ashley Young does. Preposterous dive!— Gary Lineker (@GaryLineker) November 3, 2015
United did win the Group B encounter at Old Trafford, though, thanks to Wayne Rooney’s goal in the 79th minute.
Meanwhile, in Spain, Real Madrid defeated Paris Saint-Germain 1-0 in Group A.
The 27-year-old Argentina international took three shots, had a pass accuracy of 84%, created two chances, put in eight crosses, attempted eight dribbles, and made two interceptions and two blocks.
Watching this Madrid game and all I keep thinking is how the hell have man Utd let di Maria leave the club!— Jermaine Jenas (@jjenas8) November 3, 2015