The striker had been on the pitch for only four minutes before he volleyed the ball home from a corner to put his side on level terms with the match nearing its conclusion.
Wolves' goal also came from a corner - Ethan Ebanks-Landell scoring with a 15th-minute header against the run of play.
Dougie Freedman named an unchanged side to the one that beat Fulham 3-0 last weekend.
That meant Michael Mancienne kept his place alongside Matt Mills in central defence and Jack Hobbs had to settle for a place on the bench on his return from suspension.
Chris O'Grady and Nelson Oliveira continued as a front pairing, while Jamie Ward took his place among the substitutes.
Forest started the game brightly and had their first chance on two minutes. Lansbury's corner found Matt Mills in space. He nodded the ball down for Eric Lichaj six yards out and, with his back to goal, the American stooped to head it goalwards. He couldn't find the target.
Oliveira had his first attempt shortly afterwards, holding the ball up well, checking on to his left foot and shooting from 25 yards. The ball was comfortably collected by Carl Ikeme.
Freedman's men were playing some excellent football in the opening exchanges but found themselves a goal down with 15 minutes on the clock. Ryan Mendes conceded a free-kick in a deep crossing position and Jordan Graham swung the ball towards the back post. Ebanks-Landell snuck in around the back to head the ball low past de Vries.
Moments later The Reds had a similar opportunity to equalise. Jack Price was booked for a cynical foul on Mendes and Henri Lansbury crossed the ball for Mills, who had drifted into an unmarked position in the area. From around eight yards out, Mills managed to generate excellent power on his header but the direction caused no problems for Ikeme, who held on with ease.
Forest had the ball in the net minutes later but O'Grady's tap-in from Oliveira's cut-back was correctly ruled out for offside.
And the frustration continued for O'Grady, who could only volley the ball over the bar with a left-footed volley on 33 minutes following a scrappy passage of play in the Wolves box.
The Reds were in control but they were almost hit with another sucker punch with nine minutes to play in the half. Mancienne's clearance was closed down, releasing Adam Le Fondre down the right. The striker raced into the area but his shooting angle was tight. Mills applied some pressure with a sliding challenge and nearly diverted Le Fondre's shot beyond de Vries. The Dutch keeper was able to make the save and the danger was cleared.
With half-time approaching, neat interplay between Mendes and Osborn resulted in the latter firing the ball over from 20 yards, a minute before Mancienne went into the book for a foul on Le Fondre.
The hosts claimed the final chance of the first half when James Henry cleverly slipped Graham into the area. Covering defender Mancienne did enough to put Graham off and the winger could only find the side-netting with his shot.
There were no changes for either side at the break and the first second-half incident of note saw Lansbury enter the book for a trip on Henry.
Forest's first opening of the half came just after the hour when Lichaj robbed Graham of possession on the edge of the Wolves area, nudging the ball to O'Grady. The forward could only fire it wide as a half-chance passed Forest by.
The Reds' next chance came from more superb work by Lichaj. The right back showed great strength to win the ball inside his own half before tearing away down the wing. His low cross picked out Oliveira, who tried to catch his marker off guard by changing direction as soon as he received the ball. The Portuguese international lost his footing at the crucial moment and Wolves were able to clear.
Freedman's first change followed as Ward replaced O'Grady with 67 minutes on the clock. The move saw Mendes join Oliveira up front, with Osborn switching over to the right.
But it was Wolves who would have the next big chance, Dominic Iorfa heading Graham's corner wide with 15 minutes to go.
Graham took matters into his own hands moments later, cutting in from the left and curling the ball straight at de Vries from range.
Forest's final changes saw Mendes and Osborn make way for Blackstock and Jonny Williams as Freedman bolstered his attacking options 13 minutes from time.
And it turned out to be an inspired switch as Blackstock put his side level moments after entering the fray.
The equaliser came from Lansbury's corner, which saw the ball sail over everyone in the middle towards the back post. Blackstock watched it all the way and volleyed it home in composed fashion.
Forest had to be wary in their own area shortly after play resumed. Pinillos rose well to half-clear a corner with his head. The ball dropped for McDonald on the volley and he struck it sweetly towards the top corner. Pinillos recovered in time to block the ball's path.
Oliveira was the next man in the book for bringing down McDonald as he advanced towards the Forest area.
Four minutes were added on at the end of the match but neither side were able to find the winning goal.
Forest: De Vries, Lichaj, Mancienne, Mills, Pinillos, Lansbury (c), Vaughan, Osborn (Williams 78'), Mendes (Blackstock 78'), Oliveira, O'Grady (Ward 67')
Subs not used: Evtimov, Hobbs, Trotter, Tesche
Goal: Blackstock 80'
Bookings: Mancienne 41', Lansbury 54', Oliveira 88', Blackstock 90'
: Ikeme, Iorfa, Batth (c), Ebanks-Landell, Golbourne, McDonald, Price, Edwards, Henry, Graham, Le Fondre (Afobe 84')
Subs not used: McCarey, Doherty, Coady, Byrne, Wallace, Holt
Goal: Ebanks-Landell 15'
Bookings: Price 17, McDonald 31'
Referee: Keith Stroud
Attendance: 20,000 (857 away)