Barry Robson was sent off on his home debut as Middlesbrough's Coca-Cola Championship promotion hopes suffered another setback following a 0-0 draw with Bristol City.
Midfielder Robson, a recent signing from Celtic, was given his march orders early in the second half for a second bookable offence but Gordon Strachan's side still had more than enough opportunities to see off their opponents.
Chris Killen spurned a host of opportunities to give Strachan only his second home win since arriving at the Riverside Stadium against a disappointing Robins side who were thrashed 6-0 by Cardiff at Ashton Gate in midweek.
Gary O'Neil had an early chance to put Boro in front but the skipper fired his right-footed finish wide after being picked out by right-back Tony McMahon.
The visitors' first opportunity fell to recent signing Jamal Campbell-Ryce, with the winger firing his shot straight at Boro keeper Danny Coyne from the edge of the penalty area.
Killen was presented with an opportunity to open his goalscoring account for Boro but the striker's effort was comfortably dealt with by Dean Gerken.
Former Celtic striker Killen had another chance to put his side in front 12 minutes before the break but he headed Leroy Lita's cross wide of the target.
Lita had a chance of his own after 42 minutes but the former England Under-21 striker shot straight at a grateful Gerken from close range.
The visitors almost caught Boro cold in the first minute of the second half when midfielder Paul Hartley flashed a shot wide of Coyne's goal.
Sought-after midfielder Adam Johnson was also off target when he tried his luck with his right foot from the edge of the area but Boro's hopes of securing all three points were hit when Robson was dismissed 11 minutes into the second half.
The recent signing from Celtic was shown a second yellow card for pulling back City's leading scorer Nicky Maynard in only his second appearances for the Teessiders.
To Boro's credit they continued to press forward and Killen somehow fired over the crossbar after being picked out by the industrious O'Neil.
The New Zealand striker ought to have redeemed himself on the hour mark but he header over the bar from six yards out, much to the frustration of the home supporters.
City were struggling to break down 10-man Boro and the ineffective Maynard was replaced by Danny Haynes with 20 minutes remaining.
But it was the home side who looked the more likely to go on and win the game and Johnson came close once again with a right-footed strike from the edge of the area that whistled past the post.
David Wheater and Killen had chances to win it for Boro in stoppage time but the game always seemed destined to finish goalless.
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