The defender has also insisted that that England's recent poor draw with Ireland is just a one off.
United were tasked with replacing their long-standing defensive duo of Rio Ferdinand and Nemanja Vidic when both left last summer after a difficult spell under David Moyes.
That saw an opportunity for Jones and Smalling to cement a place in the side. They were manager Louis van Gaal’s first choice pairing come the end of the season, with the side finishing with the fourth best defensive record in the league.
And Smalling believes he and Jones have proved last season they can be the long-term solution.
“When you consider the outgoings at centre back, players had to step in,” he said.
“I've been one of those who has had a good run, especially in the second half of the season. I think we (Jones and I) have proven we can fill the gap. It's one where it just builds over time and we've had our chance this season and now it is all about building on that next season.”
The duo is currently on England duty, as they take on Slovenia on Sunday in the final Euro 2016 qualifier of the season. If they win, the Three Lions will move nine points clear at the top of Group E with four games to go.
Expectations have been somewhat tempered though after a dire draw in a friendly with England last Sunday, and Smalling has insisted that performance was just a blip.
“It was like we had lost the game to be honest,” Smalling said.
“We felt we could have done a lot better. We know if we do the job on Sunday, qualification is near enough there and then we can go into the summer relieved and happy whereas if we don't win this game it is a long break so I don't think there will be any problems with people getting up for it.”