United lost 1-0 to Juventus in front of their home fans, in what was a tame performance from Jose Mourinhos side.
Juventus were by far the better side and welcome United to Turin on Wednesday night in the reverse Champions League fixture.
United have struggled for confidence this season, but Smalling says he and his team-mates will not make the same mistakes in Italy as they did in the first half at Old Trafford.
I think Juventus, we started the game a bit in awe, we were off the pace and they were on the front foot but the second half we showed we could give them a game, Smalling said.
We created chances and we can take that second half performance to Turin and we will be more on the front foot and I think youll see a better performance than you did, particularly in the first half.
Juve have shown they dont concede many goals and hopefully we can get on the front foot.
The first half, I think we learned from that and we showed that in the second half and on Wednesday you will see a difference.
United laboured past Bournemouth over the weekend in the Premier League, with Mourinho labelling his players performance as awful in the first half.
The Red Devils fought to win 2-1 after going behind in the eleventh minute, and Smalling insists the result only encourages him and his team-mates.
We are showing that attitude of never giving in and you can see that coming out. No matter how bad the first half was that second half we believed we were going to win the game and it is a great feeling, Smalling said.
It brings us closer together. Games are getting tougher and tougher, and closer than ever its coming down to fine margins and who can give that extra burst in the last five minutes and were going to see that a lot.
A lot of other teams will gain and lose points in that way.