QPR edge through, Foxes fire
Danny Gabbidon's header secured QPR progress 1-0 against MK Dons and set up a FA Cup fourth-round tie with Chelsea.
The Welsh defender nodded home midway through the second period after a spell of sustained pressure from the League One side.
The Dons impressed throughout against the Premier League side, but could not prevent Mark Hughes enjoying victory in his first home match as Rangers boss.
It was QPR's first win in the FA Cup for 11 years. Their last win was in an FA Cup replay against Luton Town in 2001.
Bolton secured their place as first-half goals from Kevin Davies and Martin Petrov saw them to a 2-0 victory against Macclesfield at the Reebok Stadium.
Wanderers were one up inside the first minute when Ivan Klasnic capitalised on an error by Jon Bateson and crossed for Davies, who finished from close range, before Petrov doubled their advantage in the 26th, firing in from just outside the area.
It was looking like a comfortable evening's work for the hosts, but the Silkmen improved after the interval and were unlucky not to get on the scoresheet.
Jermaine Beckford completed a scintillating hat-trick to send Leicester through in a comprehensive 4-0 humbling of their East Midlands rivals Nottingham Forest.
George Boateng set the tone for a dire night for the Reds, clipping into his own net following a goalmouth scramble, before Leicester took control of their own destiny through the mercurial Beckford.
The summer signing from Everton headed his first goal in 11 outings for the Foxes before sending a heatwave through the bitterly-cold King Power Stadium with two close-range finishes after the break.
Darius Henderson grabbed a hat-trick as Millwall finally found their goalscoring touch to see off Dagenham & Redbridge 5-0.
Top scorer Henderson found the net for the first time since November and Tottenham loanee Harry Kane grabbed his first goals for the club as they dispatched their League Two opponents at the second attempt.
Victory came as a huge relief to manager Kenny Jackett, who had seen his side score just once in their previous eight outings and thumped 6-0 by Birmingham just three days ago to leave them embroiled in the Championship relegation battle.
It also meant Millwall made it through to the fourth round - and a home tie with Southampton - for only the third time in eight attempts since they lost the 2004 final to Manchester United.
The other FA Cup replay, between Wrexham and Brighton & Hove Albion, was postponed until Wednesday due to a frozen pitch - a game which will be live on ESPN in the UK.