Boro win 5-4 on penalties
Middlesbrough will play Manchester United in the FA Cup quarter-finals after beating West Brom on penalties.
Viduka scored his 12th goal of the season
With the score at 4-4 after 10 penalties, George Boateng scored, only for Sherjill MacDonald to blast over.
In normal time Darren Carter had curled the ball past keeper Brad Jones to give West Brom a deserved first-half lead.
But Mark Viduka equalised for Boro in the second half, drilling the ball past Dean Kiely, while West Brom had Nathan Ellington sent off in extra-time.
606 DEBATE: Your thoughts on Boro's win
Ellington was sent off for a dangerous tackle on Parnaby, who had set up Boro's equaliser.
West Brom had had he better of the first half, before Boro came back into the game after the break.
And once Ellington was dismissed West Brom appeared content to take the game to penalties, while Boro were unable to finish the game off despite their numerical advantage.
Boro are making a habit of FA Cup ties on penalties - Gareth Southgate's reached the fifth round after beating Bristol City 5-4 on spot-kicks.
First-choice goalkeeper Mark Schwarzer had been in goal for Boro in that game, but due to a back injury he was replaced by Jones, who was playing for the Premiership side for the only the fourth time this season.
Jones was quickly into action, first touching away Paul McShane's header and then saving an Ellington shot.
Ellington set up Carter's goal, touching the ball into the path of the West Brom midfielder.
Carter reached the edge of the penalty area before sending a precise left-footed shot past Jones, who mysteriously remained on his feet rather than diving.
Boro were strangely subdued with too many passes going astray, with Stewart Downing, Viduka and Yakubu all particularly out of sorts.
The best Boro could manage in the opening half was a low Boateng shot that Kiely comfortably saved.
Boro manager Southgate brought on James Morrison at the start of the second half.
Morrison's introduction reinvigorated the Boro midfield and that had the effect of enabling Viduka to see more of the ball and eventually to deliver the equaliser.
After Parnaby's cross reached the unmarked Vikuda he was given too much time by the West Brom defence and the Australian crashed a shot past Kiely.
In the closing stages of the first half Viduka was replaced by Lee Dong-Gook and almost immediately the Korean had a chance to win the tie for Boro, only to be denied by Kiely, who came out quickly to narrow the angle.
Early on in extra-time West Brom were reduced to 10 men when Ellington received a straight red card for a reckless tackle on Parnaby.
Dong-Gook continued to trouble the West Brom defence with some electric running but the home side held on for penalties.
The Korean forward missed a penalty for Boro, but then so did Neil Clement and then the 22-year-old MacDonald, who is on loan from Anderlecht, missed with a nervous kick.
West Brom manager Tony Mowbray:
"It's the worst case scenario - extra-time, penalties and Nathan Ellington sent off.
"But we have to take the positives and gather ourselves together.
"We've 11 games to win promotion to the Premiership. It's going to be a tough task, but on the plus side that was only our second defeat in 19 games."
Middlesbrough manager Gareth Southgate:
"We have shown fantastic character to come through.
"We were really poor in the first half, but after that the the lads came back and played well and we looked the more likely side to score.
We had some young lads taking the penalties but they dealt with that test very well."
West Brom: Kiely, McShane, Clement, Curtis Davies, Robinson, Gera (MacDonald 87), Greening, Chaplow (Koren 71), Carter, Koumas (Kamara 71), Ellington.
Subs Not Used: Daniels, Albrechtsen.
Sent Off: Ellington (93).
Booked: McShane, Carter.
Goals: Carter 26.
Middlesbrough: Jones, Davies (Parnaby 56), Woodgate, Pogatetz, Taylor, Cattermole (Morrison 46), Boateng, Arca, Downing, Yakubu, Viduka (Lee 86).
Subs Not Used: Turnbull, Euell.
Goals: Viduka 63.
Ref: M Riley (W Yorkshire).