Plymouth - Stand-in captain Lucas Leiva scored a rare goal to earn Liverpool a 1-0 victory at fourth-tier underdogs Plymouth Argyle in an FA Cup third-round replay on Wednesday.
The Brazilian, playing at centre-back, met countryman Philippe Coutinho's 18th-minute corner with a firm near-post header to sink Plymouth, who had drawn 0-0 at Anfield 10 days previously.
Liverpool could afford for Divock Origi to squander a late penalty, the Belgium striker seeing his effort saved by home goalkeeper Luke McCormick.
Jurgen Klopp's Liverpool, third in the Premier League, will host second-tier Wolverhampton Wanderers in round four on January 28.
Elsewhere, Southampton set up a fourth-round clash at home to 12-time winners Arsenal after Shane Long's scruffy stoppage-time strike gave them a 1-0 win over second-tier Norwich City.
Championship leaders Newcastle United beat Birmingham City 3-1 at St James' Park, Matt Ritchie scoring twice.