He had labelled his side tired and a “touch arrogant” after back-to-back defeats had seen their long unbeaten sequence come to an end. But they hit back impressively, romping to a victory at Sixfields that could easily have been by a bigger margin.
“I’m very pleased,” said Warne. “I thought our performance was very good.
“After a couple of defeats we needed to put a flag back into the ground and we performed very well.
“We limited them to very few chances and then got three good goals ourselves, which was hugely pleasing.
“It’s nice that both my strikers scored. I thought Smudge (Michael Smith) was virtually unplayable. I thought he was excellent.
“I thought Will Vaulks, who played centre-half, was very good while Matty (Palmer), who played his first game for a while, showed how he can control a game, in the second half of the game.”
Smith put Rotherham ahead before the break and second-half goals from David Ball and Richie Towell completed a victory that could have been even more comprehensive. It took Northampton until 11 minutes into the second half before they managed a shot on target.
Smith scored the opener in the 17th minute, controlling Will Vaulks’s long ball before beating former Millers goalkeeper Richard O’Donnell with a low shot.
The visitors were 2-0 up just after the hour mark when Ball latched on to Ryan Williams’s cross and his shot had too much power for the Northampton goalkeeper. Towell added an exquisite third after fine build-up work from Smith and Williams.
Northampton Town: O’Donnell, Moloney, Taylor, Turnbull, Bunney, O’Toole (van Veen 70), Grimes, Hoskins (Ariyibi 59), Hildeberto, Powell, Luckassen (Mathis 79). Unused substitutes: Cornell, Barnett, S McWilliams, Facey.
Rotherham United: Rodak, Emmanuel, Vaulks, Ajayi, Mattock (Ihiekwe 67), Taylor (Forde 66), Palmer, Towell, Williams, Ball (Newell 84), Smith. Unused substitutes: Wood, Price, Yates, Lavery.
Referee: B Toner (Lancashire).