Town manager Joe Royle conceded his side have gone off the boil after the 1-0 defeat to Wigan saw the Blues drop to three points behind the top two.
Royle said: "We have gone off the boil. We don't have a goal in us at the moment and that is a concern.
"We didn't create any chances for our strikers today but sometimes you have to do that yourself.
"The service to Roberts and Ellington wasn't that good but on that evidence, they proved why they are the best two strikers in the league.
"I call them the push-and-pull twins but there is no doubt they are a terrific pair together. They are very dangerous and their goalscoring record reflects that."
Royle admitted Wigan deserved the win but felt that Fabian Wilnis's challenge which led to the spotkick was not a foul and was in any case outside the penalty area.
Nathan Ellington, who netted from the spot, had earlier annoyed fellow 'twin' by not laying the ball across to him. Boss Paul Jewell joked after the game that it was still a bone of contention between the pair: "I don't think they have made up yet!
"We were a bit disappointed just to be one-up at half-time but we rode the storm a bit after that and Ipswich only really had one shot - and that was a freekick.
"Nothing was ever going to be decided today but this is a big result for us and takes us three points closer to where we want to be."
Despite going back to the top of the table, it wasn't all smiles for Wigan. Greater Manchester Police are threatening to close their ground as the Latics owe them £300,000 in unpaid policing bills.
The row over police costs - which are significantly higher than Preston's who are served by a neighbouring force - has been rumbling on for a few months and the Manchester chief constable is set to have the Latics' safety certificate revoked from Monday, which could potentially see the JJB Stadium locked and Wigan unable to fulfil their home fixtures - a move which would almost certainly see the Latics docked points.
Greater Manchester Police are unwilling to accede to Wigan chairman Dave Whelan's suggestion that the matter be resolved by the courts and neither side seems keen to back down at this stage.
Manager Jewell says Wigan feel they are being treated unjustly: "For 18 months now, this club seems to be paying substantially more than anyone else for its policing costs. That seems to be a grossly unfair situation."