Lukaku, as the club’s leading goalscorer, would have been expected to step up for at least one of those attempts, especially having been branded “untouchable” by Mourinho prior to the contest.
The Belgian has, however, also failed from 12 yards this season – against Leicester in August – and Mourinho insists there is no “drama” regarding his rotation policy.
He told reporters after a 2-0 win for his side at Old Trafford: "I don't understand why everyone asks me the same, I am paid to take decisions good or bad.
"In the first half, the decision was bad. In the second half, I made another decision and I don't see the drama.
"The penalty-taker for this match was Martial, he was not even on the pitch for the second one. Romelu wants to take, he has the personality and character to take the responsibility, [Ander] Herrera was the same, but my decision was based on training in the past couple of days.
"The players respected my decision and that was it, end of story."
While happy to discuss the penalty saga, Mourinho was rather less forthcoming when it came to offering an opinion on the performance of his team as a whole, with the Portuguese in a spiky mood following recent criticism of his methods and discontent in the stands.
"It's better for the specialists to comment on the game than for me to give my opinion," he told BT Sport.
"I am paid to work and do my best, which I do every day. The specialists are paid to comment on my work, so let them comment."
He continued: "I'm more than happy [with the performance]. We change a lot of players, we broke the natural dynamic and routine of the team.
“We played a kid from the academy [Scott McTominay], we scored two goals, we didn't concede, three more points, more money for the club because every victory means more money, no significant injuries, just something in Jesse [Lingard's] back which is not important...
"I'm more than happy."
"We didn't qualify yet? See? Four victories and it's not enough. We must get that point," added Mourinho.
With another positive step taken in Europe, United can now turn their attention to a crucial Premier League clash with fellow title hopefuls Chelsea at Stamford Bridge on Sunday.