The Reds won both legs of their quarter-final tie, defeating Manchester City 3-0 at Anfield last week before finishing the job at the Etihad Stadium on Tuesday.
Liverpool also defeated City 4-3 in Premier League action on January 14 – the first loss of the league campaign for Guardiola's side.
City did manage to defeat the Reds 5-0 back in September in the sides' first meeting of the 2017-18 season.
That win helped establish City's early dominance in the Premier League, with Guardiola's men now on the verge of clinching a league title with a month to spare.
The Spanish manager will hope to have better luck in Europe next season, as he's now failed to make the Champions League semi-finals in both of his campaigns with Man City after reaching the last four in each of his first seven seasons in the competition while managing Barcelona and Bayern Munich.
With his seventh win over the Spaniard, Liverpool boss Jurgen Klopp has also now beaten Guardiola more times than any other manager.