Central defender Smalling will turn his attention back to club duties after impressing in England's World Cup qualifiers with San Marino and then Tuesday night's 1-1 draw in Montenegro.
United take on Sunderland at the Stadium Of Light on Saturday - the scene of despair last May after Manchester City scored two late goals against QPR to snatch the title on goal difference.
And Smalling said: "The way we lost title at Sunderland has been a motivating force all of this season.
"Even when we've been a goal behind, there have been a lot of comebacks to get things from games.
"I think people have been looking back at last season and you don't want to experience that feeling again. I think it has shown throughout the whole season so far.
"It was one of those situations, going into the Sunderland game, where we didn't think we had a chance.
"But to get so close in the end to winning the title, makes it even worse.
"I wasn't involved that day because I got injured in the previous game against Swansea so, if anything, it was a double blow."
Smalling is hoping to make an impact with United, who play two matches in three days with an FA Cup replay at Chelsea on Monday following on from the Sunderland clash.
He said: "We've got Saturday-Monday, and there are a lot of games coming up.
"Now that I'm back playing (after injury), I hope to make an impact and keep the season going.
"They are two big games, one in the league and one in the cup, and could go a long way to deciding those competitions."
Smalling impressed against Montenegro danger duo Stevan Jovetic and Mirko Vucinic but admits England were disappointed not to secure a win after leading at half-time through Wayne Rooney's goal.
He said: "It was good to play two games, especially this one against Montenegro which was an important one.
"It was good experience against two top players in an atmosphere that can be daunting but it was one I really relished.
"But the dressing room was pretty flat afterwards. Everyone came in and it was more like a loss than anything after we played so well in the first half.
"We really dominated and if we had got the second goal, it probably would have been a different game."
Smalling added: "I'm not too sure why the game changed so much. In the first half we passed it really well, we pressed them high, maybe we dropped off a little bit.
"But a lot of us are not sure why that really happened because after dominating for 45 minutes, we really should have kept it going."
Questions have now been asked about England's capacity to qualify, but former Fulham man Smalling sees grounds for optimism.
He believes the fact England have three of their final four games at home could be a crucial factor.
He said: "The manager (Roy Hodgson) emphasised that three of the last four games are at home and at Wembley we feel very strong.
"Do we probably need 10 points? I think so. That's the points (total) we were talking about.
"But, with the three games at home, we are very confident and, even though the second half was disappointing, we can take a lot from that first half."