This has been a difficult campaign at Old Trafford, where Louis van Gaal has struggled to follow-up a solid start to life in the hotseat.
United sit sixth in the Barclays Premier League with only nine matches remaining, increasing the importance of Sunday's short trip to Manchester City's Etihad Stadium.
Thursday's 1-1 draw with Liverpool led to them bowing out at the last-16 juncture of the Europa League, with the 3-1 aggregate loss meaning Champions League football will only return if they can break into the top four.
Manuel Pellegrini's side currently occupy the last spot and boast a four-point cushion over United - a gap that Smalling, one of the few highlights in a disappointing season, is determined to narrow on Sunday.
"It doesn't stop," the England defender said
"Luckily we've got another big game to get another reaction. There's nothing like a derby.
"I think it is (the best way to recover). We're going to want to make sure we go into that international break on a high.
"The only way we can close the gap on the top four is by beating somebody who's already in there. It's our time to step up."
United's hopes of ending the season with a flourish are not just restricted to the league, given they also have an FA Cup quarter-final replay at West Ham to look forward to.
Smalling is confident they can be successful on both fronts if they can replicate Thursday's first-half display against Liverpool.
Anthony Martial's penalty gave United a lead their performance deserved, increasing the belief that they could yet overturn the 2-0 first-leg defeat at Anfield.
However, Philippe Coutinho's moment of individual brilliance just before half-time ended those hopes, with the wonderful away goal all but ending the tie as a contest.
"I think we started the game very well and we pressed them," Smalling said.
"We knew we had to make up for that last performance and I think we did o n the whole
"It was just such a killer to concede pretty much with the last kick before the whistle. It just took the life out of us in the second half
"I think we all believed that, if we started well, we could put them under pressure.
"You could see that they started to crumble, but it was unfortunate we conceded just before half-time and it was a real battle on our hands.
"I think we all knew we gave ourselves far too much given that first performance and we paid the price for that."
Source: PA