The Red Devils play their final group game at home to Shakhtar Donetsk on Tuesday knowing that they have already made it into the last 16 of the competition.
However, United will secure top spot in Group F if they avoid defeat against the Ukrainian giants.
"It's important to [finish top of the group] and give ourselves the best possible chance in the next round," the Scot told reporters.
"It's important to give ourselves the best possible chance that we have in the next round, but the big job was to qualify in the group and that's already been done."
United are unbeaten so far in this season's Champions League thanks to three wins and two draws.