Yakubu came off the bench to score his first goal for Reading and secure an FA Cup fifth-round victory at Derby.
Hal Robson-Kanu gave the visitors a 53rd-minute lead after Stephen Warnock had been sent off on his Derby debut for fouling Jamie Mackie.
Darren Bent’s fifth goal in as many games levelled the scores in the all-Championship tie eight minutes later.
With a replay beckoning, January signing Yakubu fired in a low left-footed shot.
Rams boss Steve McClaren opted to make seven changes to the side that drew 2-2 with Bournemouth in the league in midweek with Derby pushing hard for promotion in the Championship, just one point behind leaders Middlesbrough.
January signings Jesse Lingard – on loan from Manchester United – and former Leeds United captain Warnock were given their first starts, but the latter lasted just 39 minutes at the IPro Stadium before he was shown a second yellow card for a tough tackle on Jamie Mackie.
And Josh King’s hat-trick helped Blackburn shock 10-man Premier League side Stoke and reach the FA Cup quarter-finals.
Peter Crouch reacted quickest to poke Stoke ahead from close range.
But Championship side Rovers were level when forward King, who had earlier hit the crossbar, made amends by flicking in the equaliser from a corner.
Geoff Cameron was sent off for bringing down King, with Rudy Gestede converting the penalty, before King raced clear to score twice with similar strikes.
It was an embarrassing return to Ewood Park for Stoke boss Mark Hughes who managed Rovers for four years, guiding the side to an FA Cup semi-final in 2007.
Current manager Gary Bowyer – youth team coach under Hughes – stated before the match that Hughes had “taken the club to another level”.
In the early kick off, Record signing Brown Ideye scored twice as resurgent West Brom thumped West Ham to reach the FA Cup quarter-finals for the first time since 2008.
The striker side-footed the Baggies ahead after 20 minutes before a 25-yard shot from James Morrison made it 2-0.
Ideye headed the third goal from eight yards early in the second half, reports the BBC.
West Ham substitute Morgan Amalfitano was sent off for pushing Chris Brunt in the face before Saido Berahino drove in the final goal at the near post.
West Brom are still fighting against relegation in the Premier League but manager Tony Pulis – who has lost just one in his first eight games in charge – had made it clear he also wants a sustained cup run.