Jota's first league goal since mid-January was potentially one of his most important of the campaign as the 1-0 victory kept second-placed Arsenal at more than arm's length.
It also ended Everton manager David Moyes' nine-match unbeaten league run since taking over in January and extended his personal record to 22 Anfield visits without a win.
But the main talking point on Wednesday night was Everton defender James Tarkowski seemingly getting away with an excessive challenge on Alexis Mac Allister.
Sam Barrott had never refereed at Anfield before, never mind handled a Merseyside derby, and there were times when it looked like he was reluctant to make a decision.
None more so than Tarkowski's 11th-minute tackle which appeared to receive universal condemnation from pundits and commentators for its unnecessary ferocity.
Barrott issued a yellow card and VAR saw no reason to upgrade it, with the Premier League subsequently describing the tackle as "reckless".
It set the game on edge, which played into the visitors' hands, and they had the best two chances of the half.
Beto's goal was ruled out for offside before the striker hit a post in a one-on-one with goalkeeper Caoimhin Kelleher.
The best Liverpool could muster was a Mohamed Salah header straight at Jordan Pickford and two Ryan Gravenberch shots stopped by the England goalkeeper.
But the breakthrough finally came in the 57th minute.
Jota retrieved Diaz's backheel and jinked his way past Idrissa Gueye and Tarkowski before firing past Pickford.
In Manchester, City's Jack Grealish was on target as Leicester's slide towards relegation continued with 2-0 defeat.
The England international scored his first Premier League goal in 16 months and Omar Marmoush also struck as the champions outplayed the Foxes at Etihad Stadium to move back into the fourth Champions League qualification spot.
It was a seventh successive loss without even scoring a goal for Ruud Van Nistelrooy's side and the result seemed inevitable after Grealish opened the scoring with just two minutes gone.
Sandro Tonali blasted Newcastle United firmly into the race for Champions League qualification with a stunning strike to seal a hard-fought 2-1 win over Brentford.
Alexander Isak became the first man to score 20 Premier League goals for the Magpies in consecutive seasons, but it was Italy international Tonali who snatched the headlines with a superb winner 16 minutes from time.
Isak had given the hosts, playing for their first time since their Carabao Cup final victory over Liverpool, the lead in first-half added time with his 24th goal of the season and 20th in the league.
Bryan Mbeumo equalised with a penalty before Tonali lit up St James' Park and eased his side into fifth place.
Elsewhere, Aston Villa won 3-0 at Brighton & Hove Albion, Southampton drew 1-1 with Crystal Palace and Bournemouth were beaten 2-1 at home by Ipswich Town.
