Although anything but a classic, United won 1-0 at Norwich on Saturday to keep their hopes of Champions League football alive and push the Canaries a step closer to relegation back to the Championship.
Juan Mata struck the game's only goal in the second half after Wayne Rooney had capitalised on Sebastien Bassong's mistimed jump to set up his Spanish colleague.
The win keeps Louis van Gaal's side in the hunt for the top four, with an FA Cup final date with Crystal Palace on May 22 offering the chance for a first piece of major silverware since Sir Alex Ferguson's retirement.
And Smalling, who will then go off to the European Championships with England, knows it is all about results at such a pivotal time of the campaign and praised his team-mates for dealing with the loss of Anthony Martial to injury moments before kick-off.
"Three points is all that matters at this stage," he said.
"When we came out for the warm-up before the game we said no matter what happens out there we make sure we come back with three points and I'm sure Norwich would have said the same.
"I think it's not easy because Anthony has been terrific for us all season and a real match winner for us up front. The players who came in did well and it was a much better second-half performance."
For United, this was an 18th clean sheet in their 36th Premier League game of the season and it came despite an early ankle injury forcing Matteo Darmian off on a stretcher.
"I think we've done so well with the number of clean sheets as a team," Smalling said.
"I think when you get to the last 10 minutes it's about sticking together and making sure we hang on because we know how important it is."
While the Red Devils now have their eyes firmly fixed upwards, Alex Neil's Norwich are relying on other results to help them stay in the top flight.
The Norfolk outfit have lost four games in a row without scoring a goal and even victory over Watford on Wednesday night may not be enough.
Sunderland's superb comeback victory over Chelsea on Saturday means a win for Sam Allardyce's men over faltering Everton on the same night will relegate Neil's Norwich.
Defender Ivo Pinto, who arrived in the January transfer window, insists the players will continue to show the passion to fight for survival, even against the ever-lengthening odds.
"Every game which passes makes it harder but we have to keep fighting," he said.
"We need to start winning games. We have an opportunity on Wednesday which we can't waste; we have to get three points.
"We need to keep together as a team, which we are. While it is possible, we won't quit and stop fighting."