The black, green and gold really struggled to pick up results in 2020 as they failed to keep opposition sides out at key moments.
Individual errors were blighting them, costing them the chance to build some form.
But there has been much more resilience at Saints since the start of 2021.
So much so that they have gone from losing their final seven away matches of 2020 to winning six of their first seven in 2021.
The most recent success came at Welford Road last weekend, with Saints producing a huge show of defiance late on to secure a crucial 23-18 win against Leicester Tigers.
And Proctor, who made two try-saving interventions during the first half of that match, said: "We kind of made it hard for ourselves at the end of that game.
“We did a lot of stuff that could have meant we potentially lost the game but I think that shows how far we’ve come as a team, to be able to give them that much opportunity and still hold them out.
“But that’s the beauty of a derby, isn’t it? Both teams played right until the end and it turned out to be a good game.
“We’ve come a long way this season in terms of our defence, we’ve been working on it a lot.
“It’s never easy when you lose some boys to the bin but as a team we were still confident we could still hold them out.
“We were still backing ourselves at the end, it was just a matter of holding our discipline and not giving them easy outs and we ended up doing that and getting a couple of big turnovers so we were pleased.”
Saints return to action next weekend, when Gloucester come calling at Franklin's Gardens.
Chris Boyd's side are currently fifth in the Gallagher Premiership standings, four points behind fourth-placed Harlequins and five adrift of third-placed Sale Sharks.
And with five regular-season games to go, Proctor said: "That’s obviously our big goal for the season, to be there or thereabouts at the end in terms of play-offs.
“We’re still holding that fifth spot, but that’s our out-and-out goal from here on out to be in that top four at the end of the season. So a win (against Leicester) was massive for us.
“We’ve had a week off to try to put the feet up a little bit and come back in fresh for Gloucester at home.
“It’ll be another couple of huge games for us if we want to continue pushing to get into that top four.”