Northampton sit fourth in the Aviva Premiership heading into their game against Leicester Tigers at Franklin’s Gardens on Saturday.
Jim Mallinder’s men are just four points behind their local rivals, who currently occupy second spot.
But Day believes his side could, and perhaps should, be higher in the standings, having won 12 league games, which is the same as Tigers and third-placed Harlequins.
“We’ve won as many games as anyone apart from Saracens,” said Day.
“You’ve got to look at the games we’ve lost at home that we shouldn’t have lost and you’ve got to look at the fact we’ve taken home records away from teams like Wasps, Gloucester, Bath.
“Really we should be disappointed with our league position. We’ve lost games at home we shouldn’t have lost and we’ve performed badly here so we’re certainly up there as a top four team and getting into those play-offs. Then, in the big game, getting the win.”
From a Saints perspective there would be few better games to get the victory in than a derby clash with the Tigers at the Gardens.
But Day is keen to let the fans focus on the rivalry as he and his team-mates concentrate on overhauling one of Europe’s premier teams.
“I think any time you play teams around the top six you know you’re playing international players in practically every single position so Leicester are no different to that,” he said.
“The rivalry is close, but the players come from all over the place and the fans are probably the ones who are most worried about geography.
“Leicester is a massive test whether you play for an English club, a French club, Leicester Tigers have been at the pinnacle of European rugby for some time now.
“We know they’re coming here to test us once again, they’ve got the better of us the past few times so we know we need to up our game and hopefully get the win.”
Though they have not won the Premiership since 2010, Leicester remain the kings of England as far as titles are concerned.
They have claimed three of the past six league crowns and for that reason Day still sees them as the team to Saints should measure themselves against.
“They attract the biggest crowds, they’ve got the biggest players and they win the most trophies,” he said.
“That’s not to take anything away from Harlequins and Saracens who’ve won the league in the past couple of years. They’ve shown Leicester can be beaten.
“But I still think Leicester are considered to be the biggest club in England and will give us a stern test this weekend.”