Harry Redknapp's 30th anniversary as a football manager turned ugly in injury time as he was hit in the face with a ball thrown by a steward moments before Millwall equalised through Jermaine Easter.

The Millwall substitute shot into the far corner with an unerring finish, adding to an earlier strike from Scott McDonald, as QPR's extraordinary run of 13 hours without conceding a league goal was halted. It was a valuable point for Steve Lomas's side, who were seldom outshone by their monied opponents. Redknapp looked less than amused by it all.

"We had four forwards on the pitch at the end and went for it," said Lomas. "It was a great finish from Jermaine to come off the bench and execute it, but it's no more than the lads deserved."

Millwall had suffered bruising defeats in their last two matches, conceding five goals at Bournemouth and four at Birmingham, and their manager must have rued the timing of such a tricky fixture against his former boss and mentor, Redknapp.

Following an energetic opening, the home side were incensed when Niko Kranjcar gave QPR the lead in the 26th minute. There was nothing controversial about the Croatian's slick finish from the edge of the box – and nothing the Millwall goalkeeper, David Forde, could have done to stop it – but it was preceded by a strong penalty appeal at the other end. The Millwall midfielder Liam Trotter appeared to be bundled over by the QPR striker Charlie Austin but the referee dismissed his claims.

Trotter protested even as the teams took to the centre-circle for the restart, such was the iniquity in his opinion.

"For me it was a blatant bodycheck, but us conceding a goal off the penalty incident is our fault," said Lomas, refusing to look at the final result as two points denied. "It was a double whammy when they went up and scored, but I thought we had created chances in the first half against a very, very good team, so we had to take the positives."

Indeed, Trotter had flashed two headers wide for Millwall, while an earlier opportunistic half-volley from Kranjcar rattled the post for QPR. Joey Barton's attempts to wind up the home crowd by running his fingers repeatedly through his long hair earned him wolf-whistles and exacerbated the antagonistic atmosphere at the conclusion of the first half.

Six minutes into the second period, QPR were exposed when Trotter dispossessed Richard Dunne and played a neat ball to McDonald six yards out for a tap-in. It brought to an end 826 minutes of football since Redknapp's men last conceded in the league – a goal scored by Huddersfield's James Vaughan on 10 August. Nonetheless, QPR took the lead again in the 69th minute when Austin burst on to a through ball in the central channel and dinked a cute finish over the goalkeeper.

There was uproar when Redknapp was hit plum in the face by a ball in injury time as Millwall hurried to resume play with a throw-in. Redknapp's assistant, Kevin Bond, brushed it off as an "accident". It was some accident: the same thing had happened to Joe Jordan moments before, from a ball thrown from the crowd. But it was Easter's late equaliser which will have irked the visiting coaching staff most of all.