Reading 1 Middlesbrough 1:Middlesbrough slipped into the Barclays Premier League bottom three despite Tuncay's first goal for the club earning them a point at Reading.
It could have been worse for Boro and under-pressure manager Gareth Southgate after Dave Kitson put Reading ahead early in the second half.
But the visitors were worthy of their hard-fought point after enjoying at least as much of the game as their hosts.
Their bid to end that 10-match sequence at the Madejski Stadium was hardly helped by a strikeforce with only two Premier League goals between them.
One of those was Jeremie Aliadiere and, after 10 minutes of bluster from both teams, he had the first meaningful effort with a turn and shot straight at Marcus Hahnemann.
Carbon copies followed from Bobby Convey at the other end and Aliadiere again before the Frenchman capped a fine run by going down too easily under Ibrahima Sonko's challenge for referee Alan Wiley's liking.
Both sides were giving the ball away for anything more clear cut to present itself and the prospect of better to come appeared to have been scuppered when a sudden downpour arrived midway through the first half.
However, the change in climate signalled a dramatic shift on the field as Kevin Doyle's flick played in Dave Kitson, who cut inside David Wheater and blasted the ball against Turnbull.
Moments later, Boro rightly had a goal disallowed when Reading failed to clear a corner and the ball reached George Boateng, whose fine finish arrived from an offside position.
Kitson then tried his luck from long range but Turnbull, making his first Premier League appearance for 18 months, maintained his faultless display.
The lively Aliadiere almost provided the perfect knock-down for strike partner Lee, the Frenchman coming off worse in a clash of heads with the towering Sonko.
Boro really should have been ahead five minutes before half-time when Hahnemann failed to hold Aliadiere's cross-shot and the recalled Dong-Gook Lee turned the rebound back to Johnson six yards out.
Johnson's finish went straight through Hahnemann, hit the post and bounced straight into the arms of the fortunate American.
The rain had abated by the time the second half got under way and the drama briefly followed suit.
Aliadiere did his best to inject some excitement with another thrilling run eight minutes in but he lacked any support from his timid team-mates.
Moments later, Reading went ahead through the most straightforward of goals.
A monster clearance from Hahnemann saw Doyle out-jump Wheater and flick the ball to Kitson.
Faced with the onrushing Turnbull, the striker produced the coolest of lobbed volleys over the goalkeeper and into the net for his fifth goal of the season.
Going ahead inspired the home team and Doyle's low shot appeared to have been turned behind by Turnbull only for Wiley to award a goal-kick.
The referee was in generous mood, deciding stern words were enough when an ugly skirmish broke out near the corner flag.
That was nothing compared to the tirade Hahnemann directed at team-mate Sonko moments later after the defender simply stopped playing when a cross was whipped in, which Aliadiere almost glanced in. The Royals pair almost came to blows over the issue.
Southgate then made a double substitution, bringing on Robert Huth and Tuncay for Jonathan Woodgate and Lee.
Tuncay was involved in creating Aliadiere's latest shot, on which Sonko got a crucial deflection to make amends for his earlier dereliction of duty.
Reading boss Steve Coppell tried to shore things up by bringing on Andre Bikey for Convey 12 minutes from time.
The substitute proved his worth when he thwarted a burst into the area by Tuncay, who was also making a real impact from the bench.
And it was the Turk who netted the equaliser six minutes from time.
After a spell of severe pressure from the visitors, Tuncay rose highest to nod Luke Young's pinpoint cross past the helpless Hahnemann.
Coppell introduced Shane Long for Brynjar Gunnarsson but it was Kitson who should have snatched a stoppage-time winner when he headed Nicky Shorey's cross over the top.