After Manchester City moved to the summit with a hard-fought triumph of their own against Tottenham just over 24 hours earlier, the Reds were made to sweat in the April sunshine by a side occupying the final relegation spot in the table.
Eventually, Liverpool found a clever way to break down a stubborn Cardiff defence, Georginio Wijnaldum meeting Trent Alexander-Arnold's corner with a powerful first-time finish.
A foul on Mohamed Salah by Sean Morrison allowed James Milner to wrap up a ninth successive win in all competitions for Jurgen Klopp's side from the penalty spot, meaning they now sit two points clear of the reigning champions, who have a game in hand.
After booking their place in the Champions League semi-finals in midweek, Liverpool returned to domestic duties knowing only a victory would suffice in the Welsh capital.
Roberto Firmino carelessly lifted their best chance of the first half over the top, wasting good work by fellow forwards Salah and Sadio Mane as his left-footed shot cleared both the advancing Neil Etheridge and the crossbar.
Cardiff's goalkeeper was needed to make a close-range save to deny Salah shortly after, though Liverpool did not pick up the pace until after the interval, leading to Wijnaldum’s 57th-minute strike from a well-worked set piece.
Having wasted a free header with the score at 1-0, letting Alisson off the hook after the goalkeeper had failed to deal with a corner, Morrison was adjudged to have pulled down Salah in the other penalty area, allowing Milner - who replaced fellow substitute Fabinho due to a head injury - to put the result beyond doubt.
5 - Mohamed Salah has won five penalties this season in the Premier League, only Wilfried Zaha (6) has won more. No other Liverpool player has earned more than one. Precarious. #CARLIV pic.twitter.com/xhpR94zhU1— OptaJoe (@OptaJoe) April 21, 2019
What does it mean? Over to you, City
For some time now, the Manchester derby has appeared the crucial fixture in deciding who will be crowned champions.
Pep Guardiola’s side can leapfrog Liverpool again with victory at Old Trafford on Wednesday, putting them in pole position to retain their title with three games remaining. Astonishingly, Klopp’s squad could end up as bridesmaids on 97 points.
Gini shows his bottle
Wijnaldum's form has dipped during recent weeks, yet the midfielder made a crucial impact in a must-win situation, showing excellent technique to slam home a rolling ball.
Morrison's unwanted impact
The Bluebirds captain had a glorious chance to nod in an unexpected equaliser only to fluff his lines, while his grappling with Salah ended any hopes the home side had of getting something from the game.
Key Opta facts
- Liverpool have now amassed 88 points in the league this season - it is their best ever total in a Premier League season.
- The top six teams have won all 33 of their Premier League matches against the current bottom three teams in the table this season. This is a top-flight record; surpassing 30 wins in such games in 1891-92, 1978-79, 1985-86, 2001-02, 2011-12 and 2013-14.
- Liverpool have now won nine consecutive matches in all competitions, their longest winning streak since April 2014 under Brendan Rodgers (also nine games).
- Cardiff have now lost each of their four Premier League matches against Liverpool, conceding 15 goals in all, more than they have against any other opponent in the competition.
- Georginio Wijnaldum's goal for Liverpool was just his second to be scored away from home in the Premier League, with the other 19 all coming in home games.
- 10 of James Milner's last 12 league goals for Liverpool have come from the penalty spot - nine of those also came away from home.