Ipswich manager Paul Lambert praised his “fantastic” defence, while Millers counterpart Paul Warne was left scratching his head at how his side came away without any reward.
Ipswich had to weather a storm of attacks during the second period. Rotherham had 18 attempts compared to three from the home side, but the important statistic was the result that moves Ipswich to 18 points, seven behind Rotherham, who occupy the final safe position.
Hull loanee Will Keane scored the only goal of the game 31 minutes in to give Ipswich just a third win of the season.
Warne believed that his side’s second-half display at Portman Road merited at least a share of the spoils, Michael Smith wasting a gilt-edged chance with a point-blank header before Joe Mattock blazed over from the edge of the area.
Warne claimed: “I thought the team performance was outstanding.
“We can take a lot of confidence in that we have come away from home and limited the home team to one shot.
“It was literally one-way traffic. We did everything we could to win, but unfortunately for us it did not drop for us. You can’t ask any more from our team, we just need to take our chances.”
Ipswich struck when Sean Raggett failed to cut out Freddie Sears’s cross and Keane slammed home his goal from inside the six-yard area after he miscontrolled with his initial touch of the ball following a cross from the left by Freddie Sears.
Keane was one of four Ipswich debutants alongside veteran centre-back and free agent James Collins, defender Callum Elder and Huddersfield Town striker Collin Quaner, who all signed in the January transfer window.
Warne added: “It was a bit of an error for the goal, but there are always errors when goals are conceded.
“I could be standing here after a 3-1 win, but that wasn’t the case. Goals change games, but our performance was excellent.
“We penned them in for the second half of the game, so it’s disappointing for the lads that they haven’t got anything. We conceded with their only shot on target, which was a killer for us.”
Lambert said: “I thought James Collins and the other new lads were outstanding. James wanted to be here, which was great, and to come and do what he did here was unbelievable, along with Will Keane, who has not played for a long time. They will get fitter and up to match speed and give everybody a lift.”
Ipswich Town: Gerken, Pennington, Chambers, Collins, Elder, Skuse, Chalobah, Lankester (Dawkins 74), Keane, Sears (Nsiala 90), Quaner (Downes 65). Unused substitutes: Harrison, Bishop, Bialkowski, Huws.
Rotherham United: Rodak, Vyner (Wood 89), Raggett (Williams 38), Robertson, Mattock, Ajayi, Forde (Yates 70), Vaulks, Wiles, Taylor, Smith. Unused substitutes: Palmer, Price, Ihiekwe, Jones.
Referee: J Linington (Isle of Wight).