Kenny Dalglish hailed his side's application after a late Dirk Kuyt goal guided Liverpool to a 2-1 win over Manchester United in the fourth round of the FA Cup.
Kuyt struck two minutes from time at Anfield to seal his team's progress and eliminate a second Manchester team from a major cup competition in four days following their Carling Cup semi-final victory over City.
The game was played against a tense backdrop following Luis Suarez's eight-match ban for racially abusing United defender Patrice Evra.
Daniel Agger opened the scoring with a 21st-minute header but Park Ji-sung equalised six minutes before the break and a replay looked likely until Kuyt's winner.
Dalglish said: "Their commitment, attitude and desire to get a result was fantastic and we cannot speak highly enough of them after that performance and result."
Evra was booed throughout by Liverpool fans but nothing untoward appeared to have happened inside the ground.
However, late on Saturday Merseyside Police announced a 59-year-old man had been detained in connection with an alleged racist gesture made at Anfield which was captured on TV footage.
QPR and Chelsea met for the first time since John Terry was charged with racially abusing Anton Ferdinand during October's Premier League clash, a charge he denies.
The Football Association agreed the teams could forgo the pre-match handshake in a bid to reduce tensions, exacerbated when the Metropolitan Police announced they were investigating a "malicious communication" addressed to Ferdinand.
Chelsea claimed a 1-0 victory courtesy of Juan Mata's 62nd-minute penalty for a debatable foul by Clint Hill on Daniel Sturridge.
Of Ferdinand, manager Mark Hughes said: "It was difficult for him as the focus seemed to all be on Anton, which is understandable given what has happened in the last 48 hours."
Chelsea counterpart Andre Villas-Boas hailed Terry, saying: "Individually from John, it was an excellent performance, very, very focused, managed to get the off-the-field events out of his mind and concentrate on his job."
Brighton provided the biggest shock, beating Premier League Newcastle 1-0.
Will Buckley scored the only goal 15 minutes from time - his shot deflected in off Mike Williamson - and Seagulls boss Gus Poyet said: "In the next round I want to be at home. The players want to play a big team away, but I don't want a heart attack."
League Two Crawley enjoyed a 1-0 win at npower Championship side Hull thanks to Matt Tubbs' 57th-minute goal.
Manager Steve Evans said: "I think we were unlucky not to win by four or five."
Last year's runners-up Stoke enjoyed a 2-0 win at Derby, Cameron Jerome and Robert Huth on target while Chris Eagles got the winner for Bolton in their 2-1 victory over Swansea.
Luke Moore put the Swans ahead but it was quickly cancelled out by Darren Pratley.
Norwich won 2-1 at West Brom, Simeon Jackson's 85th-minute goal the winner after Grant Holt and Marc Antoine Fortune struck.
League One Sheffield Wednesday went ahead through Clinton Morrison at Blackpool but were denied by a dubious penalty converted by Kevin Phillips.
Birmingham were comfortable 4-0 winners at Sheffield United thanks to goals from Nathan Redmond, Wade Elliott and Adam Rooney (two).
Darius Henderson's 86th-minute goal saw Millwall grab a replay against Southampton after Rickie Lambert had put Saints ahead at the New Den.
Jermaine Beckford scored twice as Leicester beat Swindon 2-0 while Damion Stewart's own goal put Stevenage into the fifth round for the first time in their history as they beat Notts County 1-0.