Sunderland looked to have done enough for a victory after James McLean struck on 70 minutes with a clinical low drive, however striker Nathan Tyson came off the bench to head home from close range and level the match.
After a quiet opening 10 minutes at Pride Park, the game burst into life as firstly Michael Jacobs evaded the challenge of Ahmed Elmohamady down the left and cut the ball across the face of goal. With Theo Robinson for company, former Aston Villa central defender Carlos Cuellar diverted the former Northampton Town winger’s cross onto his own post.
O’Neil’s side stormed up the other end of the pitch in a swift counter attacking move. Ireland international midfielder James McLean found acres of space down the left and hit a venomous strike that forced Frank Fielding into an excellent reflex stop; tipping the ball onto his near post.
Then Rams forward Jamie Ward saw his low drive from 20-yards gathered at the second attempt by Mignolet, before the away side had two chances of their own to break the deadlock.
Midfielder Craig Gardner opened up his body well and let-fly with a 25-yard curling effort that Fielding did well to tip behind. The resulting corner eventually found its way to Spanish defender Cuellar, who smashed the loose ball against the foot of the post from 12-yards out.
On the half-an-hour mark, Ward found another pocked of space in between the Sunderland midfield and defence and once again the 26-year-old made Mignolet work with a low drive from 20-yards out.
Like the first-half, the two sides spent the opening 10 minutes feeling each other out, before Academy graduate Will Hughes bucked the trend and waltzed his way past three visiting defenders, but sliced his right-footed effort wide of goal from the edge of the penalty area.
68 minutes in and England international striker Frazier Campbell latched on to a cleaver through ball from Sebastian Larsson, but the former Manchester United forward stumbled at the vital moment, and a combination of Fielding and Richard Keogh cleared the ball away from danger.
However, just two minutes later the Premier League side went ahead as Kieran Richardson’s inch-perfect pass sent McLean clean-through down the left. The Irish midfielder kept his cool and slotted the ball across goal, past Fielding into the bottom corner.
After a flurry of substitutes in the final five minutes, the Rams upped the tempo in search of the equaliser. And with 89 minutes on the clock, substitutes Michael Hoganson and Tyson linked up well, as the former whipped in a dangerous ball from the left and Tyson reacted quickest to get in front of Mignolet and head home from inside the six-yard box, and seal a draw.
The Rams now travel to Chesterfield’s B2net Stadium on Saturday to round off their pre-season schedule, before Tuesday’s curtain-raiser against Scunthorpe United in the First Round of the Capital One Cup at Pride Park.
Derby County: Fielding (GK); Brayford (Gjokaj 65), Keogh, Buxtton, Naylor (Hoganson 70); Coutts (Bailey 79), Hughes (Tyson 63), Hendrick, Jacobs (Davies 85); Ward (Barrera 85) Robinson (Doyle 85).
Subs Not Used: Legzdins (GK).
Sunderland: Mignolet (GK); Elmohamady, O’Shea, Cuellar (Egan 63), Adams; Larsson, Gardner (Richardson 45), Colback (Noble 75), Meyler (Cattermole 45), McLean (Knott 79); Campbell.
Subs Not Used: Westwood (GK).
Attendance: 3,128 (668 Visiting Supporters).