Derby endured a frustrating afternoon when they were held at home for the first time this season as Ipswich fought back to draw 1-1 at the iPro Stadium.
Chris Martin pounced from close range to give Derby an early lead but, after Jeff Hendrick was taken off with what looked a serious arm injury, Christophe Berra headed in from a free-kick in the 52nd minute.
David McGoldrick was in the Ipswich team that drew 4-4 at Derby last season, but his absence from the squad only added to growing speculation that he will join Leicester on Monday.
Steve McClaren had watched Derby come back from 4-1 down then, the day after his appointment as head coach, but this time he saw his team go in front in the 13th minute.
Jamie Ward's low ball from the left was sliced into the air by Luke Hyam, and although Dean Gerken saved Martin's header and Jonathan Parr blocked Johnny Russell's follow up, Martin squeezed a shot inside the goalkeeper's left post.
Derby thought they should have been awarded a penalty in the 20th minute when Hendrick appeared to be caught by Berra, but referee Eddie Ilderton let play continue and the midfielder was replaced minutes later with an injured right arm after he fell awkwardly.
Ipswich got a foothold in the game without creating a clear chance, although it needed a well-timed tackle by John Eustace to prevent Teddy Bishop running clear through the centre in the 42nd minute.
The injury to Hendrick meant six added minutes were played and Ward had a shot saved and fired just wide as Derby ended the half as they started it, on top.
However, Ipswich were back in the game seven minutes into the second half when Paul Anderson swung over a free-kick from the left and Berra planted a downward header past Lee Grant from 10 yards.
Grant denied Anderson two minutes later and turned over a 25-yard shot from Bishop before Martin headed a Cyrus Christie cross just over in the 58th minute.
Gerken saved superbly from Ward as Derby responded, but Ipswich were also dangerous and Martin had to head away a Daryl Murphy header before he fired wide at the other end.
Best had a chance to put Derby back in front in the 82nd minute when he headed a Craig Bryson corner over from 10 yards, but Hyam gave the home side a scare in the 87th minute when he almost turned a cross past Grant.
Martin had a shot deflected just wide as Derby pressed hard in stoppage time, but Ipswich deservedly held on for a hard-earned point.