Aguero's hat-trick saves City
Manchester City kept their quadruple hopes alive after they survived a scare to come back from two goals down and beat Watford 4-2 in the fourth round of the FA Cup at the Etihad Stadium.
City boss Manuel Pellegrini had talked up his side's chances of securing a clean sweep of trophies this season, and few doubted Watford would pose much threat to their lofty ambitions having won just one of their last 14 games prior to Saturday.
But Watford took the lead after 21 minutes when Troy Deeney found Fernando Forestieri who controlled and shot low past Costel Pantilimon. Deeney then doubled their advantage on the half-hour as an improbable victory looked to be on the cards,
However Sergio Aguero got City back into the game though, converting Aleksandar Kolarov's cross an hour into the match.
Aguero then made it five goals in four games since returning from injury, curling the ball home for his 24th of the season.
And Kolarov completed the comeback for City, Watford keeper Jonathan Bond letting his 40-yard shot slip through his hands with just three minutes remaining to end their hopes of earning a replay.
City weren't done, however, with Aguero completing his hat-trick in injury time after heading in Jesus Navas' cross.
Goals in either half from Victor Moses and Daniel Sturridge were enough to see Liverpool overcome Bournemouth in a keenly contested FA Cup fourth round tie.
The visitors named a strong side for the game at the Goldsands Stadium and it was Luis Suarez who created both goals to see the Reds into the last 16.
Cherries' boss Eddie Howe had said leading into the game that he hoped, even if his side lost, they would show people that they could play attractive football.
That was the case for much of the game as the Sky Bet Championship outfit created more chances than their Premier League opponents - but it was the clinical nature of Liverpool's finishing which ultimately proved the difference.
Everton cruised into the fifth round of the FA Cup, but their 4-0 victory against Stevenage was overshadowed by a horrific injury to Bryan Oviedo, who was taken to hospital with a suspected broken leg.
Oviedo's left leg looked to have been snapped in two after he was caught by Stevenage midfielder Simon Heslop as he was attempting a shot on goal. Everton's players turned away in horror as the midfielder lay stricken on the floor at the Lamex Stadium.
The Costa Rican was taken to hospital and now looks set for a lengthy spell on the sidelines. Everton, who were 1-0 up at the time thanks to Steven Naismith's goal, did not let the incident affect them as they strolled to a comfortable 4-0 win
Crystal Palace were the only Premier League team to go out as holders Wigan Athletic won 2-1 at the DW Stadium.
Ben Watson, who scored Wigan's winning goal in the FA Cup final against Manchester City last season, scored against his former club nine minutes from the break, tucking home James McClean's pull-back. The first half saw eight minutes of added time after Jonathan Parr needed urgent medical attention for a clash with Wigan's Callum McManaman. Parr was taken off on a stretcher wearing an oxygen mask.
Palace then levelled through substitute Aaron Wilbraham's close-range finish, but McClean restored Wigan's lead after 78 minutes.
The lowest-ranked side in the competition - Kidderminster Harriers - will be very proud of their efforts after going down just 1-0 at League Cup finalists Sunderland.
Gus Poyet made 10 changes from the side that won on penalties at Manchester United on Tuesday, needed just five minutes to take the lead when Greek winger Charis Mavrias' controlled finish found the bottom corner.
Southampton avoided a potential banana skin against perennial giant killers Yeovil Town as they eased past the Glovers 2-0 at St Mary's.
The Premier League club hit the bar through Jay Rodriguez after 18 minutes shortly before they made the breakthrough from the penalty spot. Guly Do Prado stepped up and scored his first goals in more than two years after Jos Hooiveld was felled following a corner.
Sam Gallagher assured the Saint's place in the fifth-round when he drifted past two Yeovil defenders before slotting in from a tight angle.
Hull City also avoided an upset - but were made to work much harder in a 2-0 victory at League Two Southend United thanks to a Matty Fryatt double.
Cardiff City have now won two FA Cup games in two since Ole Gunnar Solskjaer took over when they scraped a 1-0 win at Bolton Wanderers.
Fraizer Campbell tapped in Craig Noone's cross send through Cardiff, who had lost their last 11 visits to the Reebok stadium.
Charlton Athletic won the battle of the Championship sides with Huddersfield Town thanks to Simon Church's goal as the Addicks advanced past the fourth round for the first time since 2000.
American defender Oguchi Onyewu scored what proved to be the winning goal in a 2-1 Sheffield Wednesday victory at Rochdale. Onyewu headed a corner but the Dale defence blocked his initial effort. But Onyewu smashed the loose ball through a crowded six-yard area and into the net.