Cobblers boss Keith Curle praised the 'desire' of his players after their penalty shoot-out win over Cambridge United in the Checkatrade Trophy on Tuesday night.
Town never really got out of second gear at the Abbey Stadium and struggled to respond after George Maris blasted United in front with just nine minutes gone.
But after huffing and puffing for the proceeding 80 minutes, the Cobblers finally got back on level terms thanks to Kevin van Veen, who converted Daniel Powell's cross to take the tie to penalties.
Van Veen stepped up first to score from 12 yards and with Lewis Ward saving United's first two penalties, successful spot-kicks by Billy Waters, Sam Foley and Shaun McWilliams sent Northampton into round three, within three games of Wembley.
"You wouldn't say it will go down as a classic but we showed good endeavour," said Curle. "We played another system and gave more game-time and more opportunities for some other players that haven't had much of it.
"I'm still looking at players and assessing players in training but you need that game-time because you need them on the pitch to see how they react and how they perform.
"It was a good opportunity to do that tonight and also to get some match fitness into some of the squad."
Junior Morias, Jay Williams and Lewis Ward were three players to be handed a rare opportunity on Tuesday as Curle tweaked formation again, playing 3-4-3 at the Abbey Stadium.
"It was another formation and the players are accepting challenges," he added. "We only have a limited amount of time to work on them and we're trying to give them as much information as we can, but it's their willingness and desire to make it work.
"The players have responded very well and there's a desire in the changing room to give everything they've got, which is pleasing and that showed tonight by scoring an equaliser in the last minute and then the strength of character to step up and take a penalty."