David McGoldrick netted the rebound following his second saved penalty in two games but Kevin Davies equalised as Town and Preston are locked 1-1 at half-time in their FA Cup third round tie at Portman Road.
Town boss Mick McCarthy made seven changes with Scott Loach, Tyrone Mings, Carlos Edwards, Luke Hyam, Anthony Wordsworth, Frank Nouble and debutant Sylvan Ebanks-Blake all starting in a 4-4-2 formation — with Mings at right-back and skipper Edwards ahead of him in midfield - rather than the anticipated 3-5-2 system.
Tommy Smith (back), Daryl Murphy (thigh), Dean Gerken (groin) dropped out of the 18, while Cole Skuse, Ryan Tunnicliffe and Paul Anderson switched to the bench, alongside top scorer McGoldrick.
Ebanks-Blake hit an early shot on the turn but failed to test Preston keeper Declan Rudd, who is on loan from Norwich.
Wordsworth surrendered possession inside the Town half in the 11th minute with the Blues yet to get going. Fortunately, the midfielder, a Lilywhites loan target in November, was able to get back to block Iain Hume’s shot from a tight angle on the right.
A minute later, Paul Gallagher curled a shot wide from the left with the visitors having the better of the opening spell.
Kevin Davies hit a low effort which Loach claimed comfortably in the 18th minute, then Ebanks-Blake used his strength to win the ball then struck a sharp shot from 30 yards which Rudd saw past his right post.
The visitors should have been ahead in the 21st minute when Jay Tabb gifted possession to Davies on the Preston right. The former England man sent in a great ball which Hume diverted goalwards at the far post only for Chambers to nod off the line.
It was a lucky escape for the Blues who had been far too casual against League One’s fourth-placed side. A minute later, Nouble shot just wide from 25 yards.
Ebanks-Blake’s Town debut lasted just over 28 minutes, the former Wolves man sitting down in the centre circle and briefly receiving treatment before making way with McGoldrick taking over up front.
McGoldrick made a quick impression, hitting a shot which was deflected wide in the 33rd minute. Chambers headed to Rudd from the corner.
Mings saw a strike deflect wide in the 37th minute and from the resultant corner Town were awarded a penalty. Edwards sent the ball over from the right and Paul Huntington handled ahead of Nouble. Referee Michael Naylor pointed straight to the spot.
McGoldrick, who had a penalty saved on New Year’s Day when Charlton’s Ben Alnwick saved his low effort to his left, again stepped up, this time slamming a powerful strike to Rudd’s right. Again the keeper saved, but this time the Town top scorer followed up to net his 12th of the season.
The visitors were close to getting back on terms when Rudd’s long kick from the edge of his area — Nouble clattering into the keeper after the ball had gone, an incident which was missed by the officials — and Hume went through one-on-one with Loach, who did well to save with his legs.
But a Preston equaliser wasn’t long in coming. Mings was down injured when Lee Holmes played in Davies, who would have been well offside but for the prone Blues defender, and the ex-Bolton man slipped the ball past Loach.
The League One side were certainly worthy of at least being on terms at the break, even if their goal had an element of good fortune, the much-changed Blues having put in a thoroughly under par display.
McGoldrick had improved matters after coming on but his goal came against the run of play and with the Lilywhites having had the better of the chances up to then.
Town: Loach, Chambers, Berra, Mings, Edwards, Cresswell, Hyam, Tabb, Wordsworth, Nouble, Ebanks-Blake (McGoldrick 28). Subs: Crowe, Anderson, Skuse, Tunnicliffe, Hunt, Taylor.
Preston North End: Rudd, Keane, Huntington, Wright, Davies, Holmes, Gallagher, Buchanan, Welsh, Hume, Kilkenny. Subs: Stuckmann, Laird, Byrom, Beavon, Garner, Hayhurst, Brownhill. Referee: Michael Naylor (South Yorkshire).