Bolton's victory over 10-man Middlesbrough - their eighth successive home win - ensured Dougie Freedman's side moved into the play-offs.
Bolton had numerous chances but had to wait for Chris Eagles to break the deadlock from 12 yards after the break.
Kieron Dyer converted Scott McDonald's cross from close range to level.
Parity lasted three minutes as Jonathan Woodgate was sent off for a foul on Marvin Sordell and the striker struck from the spot for a valuable win.
The victory ensured Bolton, without the injured Jay Spearing and David Ngog, leapfrogged Leicester into sixth place.
Bolton in top form
Bolton have won seven and drawn five against Middlesbrough since a 1-0 defeat in the old Third Division in April 1987.
The home team attacked from the kick-off, with Craig Davies's 18-yard effort in the second minute needing a fingertip save from Jason Steele.
Boro battled their way into the match and McDonald should have done better when presented with a chance from six yards in the 23rd minute.
Bolton looked the more likely to score, however, and they took the lead when Chung-Yong Lee released Eagles and the former Manchester United man struck for the 10th time this season.
The visitors soon levelled thanks to Dyer's header but Bolton quickly regained the lead with the help of Woodgate.
The defender felled Sordell and the striker made no mistake from the penalty spot, scoring his eighth goal of the season.
Bolton manager Dougie Freedman:
"It was a very good team performance. You've got to remember that we've played three very intense games in a week, so to hang on and dig in is what's getting us in the top six.
"The play-offs are in our own hands now, but it's still going to be difficult with us having to play Cardiff and then Blackpool.
"However it's a great thing to have at this stage of the season and we wouldn't want to have it any other way."
Middlesbrough manager Tony Mowbray:
"I thought we deserved more than that and we needed a better official to referee the game because there were some bewildering decisions out there today. The penalty was one of them and the sending-off was certainly one of them.
"Bolton started the game well, which they always do but I thought we had a decent foothold in the game and then they got a goal through a cross which just drifted in, but that's the way our luck has been going at the minute.
"I thought we were the better team but the history books will show that we lost. They won't show that we conceded a lucky goal and then a penalty, which having seen half a dozen times was never a penalty kick, but that sums up the referee's performance."
Live Text Commentary
Full Time The referee brings the game to a close.90:00 +3:23
Free kick awarded for a foul by Scott McDonald on Darren Pratley. Free kick taken by Darren Pratley.86:22 Substitution
Substitution Danny Butterfield on for Marvin Sordell.85:01
Corner taken by Richard Smallwood, Darren Pratley makes a clearance.84:16
Marcos Alonso concedes a free kick for a foul on Scott McDonald. Richard Smallwood delivers the ball from the free kick right-footed from right wing, clearance by Samuel Ricketts.82:04
A cross is delivered by Marcos Alonso, blocked by Nicky Bailey.80:55
The ball is sent over by Chris Eagles, save made by Jason Steele.79:50
Marvin Sordell takes a shot. Save by Jason Steele.79:16
Unfair challenge on Rhys Williams by Tom Eaves results in a free kick. Jason Steele takes the free kick.78:48
Unfair challenge on Chris Eagles by Richard Smallwood results in a free kick. Direct free kick taken by Adam Bogdan.72:20
Rhys Williams fouled by Tom Eaves, the ref awards a free kick. Direct free kick taken by Jason Steele.71:32 Substitution
Substitution (Bolton) makes a substitution, with Tom Eaves coming on for Craig Davies.69:00 Substitution
Substitution Nicky Bailey is brought on as a substitute for Kieron Dyer.67:23
Marcos Alonso produces a right-footed shot from long distance which goes wide right of the goal.65:41 Substitution
Substitution Sammy Ameobi leaves the field to be replaced by Andre Bikey.65:41
Samuel Ricketts gives away a free kick for an unfair challenge on Rhys Williams. Jason Steele restarts play with the free kick.63:10
Direct free kick taken by Marcos Alonso.63:10 Dismissal
Dismissal The referee sends off Jonathan Woodgate for second bookable offence.62:58
Jonathan Woodgate challenges Marvin Sordell unfairly and gives away a free kick.58:42 Substitution
Substitution Marvin Emnes replaces Josh McEachran.
Goal! - Marvin Sordell - Bolton 2 - 1 Middlesbro Placed penalty scored by Marvin Sordell. Bolton 2-1 Middlesbrough.57:02
Jonathan Woodgate gives away a Penalty for an unfair challenge on Chung-Yong Lee.57:02 Booking
Booking Jonathan Woodgate is cautioned.56:28
Justin Hoyte concedes a free kick for a foul on Chung-Yong Lee. Marcos Alonso takes the free kick.55:17
Assist by Scott McDonald.55:17 Goal scored
Goal! - Kieron Dyer - Bolton 1 - 1 Middlesbro Kieron Dyer scores a headed goal from close range. Bolton 1-1 Middlesbrough.54:19
The referee penalises Scott McDonald for handball. Direct free kick taken by Adam Bogdan.52:30
Sammy Ameobi gives away a free kick for an unfair challenge on Chung-Yong Lee. Chris Eagles has an effort direct from the free kick.50:22
Richard Smallwood challenges Mohamed Medo unfairly and gives away a free kick. Craig Dawson takes the free kick.49:14
Assist by Chung-Yong Lee.49:14 Goal scored
Goal! - Chris Eagles - Bolton 1 - 0 Middlesbro Chris Eagles finds the back of the net with a goal from inside the area to the top left corner of the goal. Bolton 1-0 Middlesbrough.47:58
Mustapha Carayol has an effort at goal. Save by Adam Bogdan.47:12
Craig Davies takes a shot. Blocked by Jonathan Woodgate.45:34
Samuel Ricketts concedes a free kick for a foul on Mustapha Carayol. Direct free kick taken by Andrew Halliday.45:01
The game restarts for the second half.45:00 +1:16 Half time
Half Time The referee calls an end to the first half.45:00 +0:53
Chung-Yong Lee decides to take a short corner.44:53
Mustapha Carayol is flagged offside by the assistant referee. Adam Bogdan restarts play with the free kick.44:03
Andrew Halliday has an effort at goal from just inside the box that misses to the right of the goal.42:27
Corner taken right-footed by Kieron Dyer from the left by-line, Rhys Williams takes a shot. Blocked by Craig Dawson.40:31
The referee blows for offside against Marvin Sordell. Jason Steele takes the indirect free kick.38:58
Craig Davies takes a shot. Save by Jason Steele.37:35
Effort from the edge of the area by Richard Smallwood goes wide of the right-hand upright.35:31
Darren Pratley concedes a free kick for a foul on Josh McEachran. Direct free kick taken by Jason Steele.34:53
Free kick awarded for a foul by Richard Smallwood on Mohamed Medo. Direct free kick taken by Mohamed Medo.34:07
Craig Davies has an effort at goal from outside the box which misses left.33:53
Unfair challenge on Chung-Yong Lee by Kieron Dyer results in a free kick. Chung-Yong Lee takes the free kick.32:22
Josh McEachran challenges Samuel Ricketts unfairly and gives away a free kick. Adam Bogdan takes the free kick.30:27
Corner taken by Chris Eagles from the left by-line.30:09
Josh McEachran gives away a free kick for an unfair challenge on Chung-Yong Lee. Chung-Yong Lee takes the direct free kick.26:52
Darren Pratley has an effort at goal from outside the area missing to the wide left of the goal.24:35
Short corner taken by Kieron Dyer.22:49
Unfair challenge on Chung-Yong Lee by Jonathan Woodgate results in a free kick. Marcos Alonso produces a shot on goal direct from the free kick, save by Jason Steele.22:15
Header from close in by Scott McDonald misses to the left of the target.19:38
Mustapha Carayol fouled by Craig Davies, the ref awards a free kick. Andrew Halliday takes the direct free kick.16:16
Unfair challenge on Jonathan Woodgate by Marcos Alonso results in a free kick. Justin Hoyte takes the free kick.15:40
Scott McDonald has an effort at goal from outside the box which goes wide right of the target.14:07
The ball is crossed by Samuel Ricketts.12:38
Free kick awarded for an unfair challenge on Scott McDonald by Craig Dawson. Free kick taken by Justin Hoyte.8:25
Scott McDonald has an effort at goal from 20 yards. Save by Adam Bogdan.5:20
Scott McDonald gives away a free kick for an unfair challenge on Craig Dawson. Direct free kick taken by Adam Bogdan.3:29
Kieron Dyer fouled by Darren Pratley, the ref awards a free kick. Direct free kick taken by Justin Hoyte.2:51
Chris Eagles decides to take a short corner.2:15
Inswinging corner taken from the left by-line by Chris Eagles, Mohamed Medo takes a shot from 25 yards. Jason Steele makes a save.1:53
Corner taken right-footed by Chris Eagles to the near post, Jonathan Woodgate makes a clearance.1:29
Craig Davies takes a shot. Save by Jason Steele.0:00
The referee gets the game started.
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