"I think they paid us an ultimate respect with the team that they picked and the subs on the bench," Wilder told BBC Radio Northampton.
"Quite a lot of the early rounds are filled in with Under-21 players and they certainly didn't.
"We were a little disappointed with the goals we conceded, but we can say there were magnificent balls in.
"A couple of times we were on the rocks and we can also say look at the unbelievable quality we were up against.
"The right winger they've just paid £12m for, Aleksandar Mitrovic and Jack Colback came on - their attitude was absolutely spot on in taking us seriously."