United were drawn with the Dutch giants in the last 32 of the Europa League.
Smalling said: “It was a massive disappointment going out of the Champions League, but look at the calibre of teams that are in the Europa League.
“We’ve drawn Ajax and they have a lot of history. That will be a good test.
“A lot of the teams will be keen to do well. Whoever wins the competition will be a good team.”
