The Norwegian's brace took his tally to 32 goals for the season, equalling the record total for a 38-game season, with reigning champions City still having eight league games remaining.
In the race to finish in the top four, third-placed Newcastle United slumped to a 3-0 defeat at a resurgent Aston Villa but were relieved when fifth-placed Tottenham Hotspur later went down 3-2 at home to relegation battlers Bournemouth.
Frank Lampard suffered a third consecutive defeat since returning to Chelsea as interim manager in the wake of Graham Potter's sacking, his side losing 2-1 at home to a Brighton & Hove Albion side still in the hunt for European qualification.
Southampton's 10-year stay in the top flight is in grave danger of ending as the bottom club went down 2-0 at home to almost-safe Crystal Palace for whom Eberechi Eze scored twice to maintain Roy Hodgson's 100% record since taking charge.
Fourth-from-bottom Everton remain in the mire after losing 3-1 at home to Fulham.
Wolverhampton Wanderers hoisted themselves further clear of the relegation zone with a 2-0 home win against Brentford.
With Arsenal in action at West Ham United on Sunday, Manchester City seized their chance to apply more pressure by dismantling 19th-placed Leicester before halftime.
City now have 70 points from 30 games with Arsenal on 73.
Defender John Stones fired City ahead from close range in the fifth minute and Haaland made it 2-0 with a penalty seven minutes later after a handball by Wilfred Ndidi.
Haaland chipped in his second in the 25th minute after Kevin De Bruyne's set up, the goal taking him level with Mo Salah's record for a 38-game Premier League campaign. He now has 47 goals from all competitions this season.
UNCOMFORTABLE START FOR SMITH
Leicester managed a consolation goal from Kelechi Iheanacho but by that stage City, who took Haaland off at halftime, were already setting their sights on next week's Champions League quarter-final second leg away at Bayern Munich where they will start with a 3-0 advantage.
"The game was tricky in the last 20 minutes. But the first 55, 60 minutes was good," Pep Guardiola, who racked up his 150th home win in charge of City, said.
For Leicester's interim manager Dean Smith it was an uncomfortable start to his rescue mission, although his side remain only two points behind 17th-placed Everton.
"You can't come here and give them a two-goal lead after 10 minutes and expect to come out with points," Smith said after Leicester's eighth defeat in nine league games.
Newcastle were beaten for only the fourth time in the league this season as Ollie Watkins scored twice in a comfortable win for Villa who have won five in a row to move into sixth place in the table. Jacob Ramsey gave Villa the lead with Watkins sealing the points after halftime.
"I think it's one of those performances that we need to analyse and move on quickly," Newcastle manager Eddie Howe said. "We weren't there today."
Villa have 50 points, with Tottenham on 53 and fourth-placed Manchester United and Newcastle United both on 56. Newcastle and Manchester United, who face Nottingham Forest on Sunday, have played fewer games than Villa and Tottenham.
AFC Bournemouth's Dominic Solanke scores their second goal past Tottenham Hotspur's Hugo Lloris - Premier League - Tottenham Hotspur v AFC Bournemouth - Tottenham Hotspur Stadium, London, the UK - April 15, 2023. (Photo: Reuters)
Tottenham took the lead through Son Heung-min and equalised in the 88th minute through Arnaut Danjuma after Bournemouth had gone ahead with goals by Matias Vina and Dominic Solanke.
But substitute Dango Ouattara won a thriller for Bournemouth in the fifth minute of stoppage time.
Chelsea needed a confidence boost ahead of their Champions League quarter-final second leg against Real Madrid next week and took the lead against Brighton through Conor Gallagher's deflected effort early on.
But Brighton hit back with goals by substitutes Danny Welbeck and Julio Enciso to ruin Lampard's homecoming.
"I'm disappointed on every level," Chelsea's all-time top goal-scorer Lampard told the BBC. "The better team won. They could have won by more. They played like a team."
Chelsea remain in 11th place.
