The Algerian curled two first-half efforts into the corner to ease any concerns about a perceived City scoring drought.
Benjamin Mendy drove home Kevin de Bruyne’s cross for his first City goal before half-time and Ferran Torres turned home his first Premier League goal after the break following a brief period of Burnley pressure.
Mahrez steered the hosts to their biggest win of the season by completing his first treble since scoring all three for Leicester City in a victory at Swansea City in December 2015 as the Foxes marched towards the title.
It could have been worse for visitors Burnley – and their keeper Bailey Peacock-Farrell, who was making his Premier League debut with first-choice Nick Pope missing because of injury.
In addition to De Bruyne slamming a shot against a post in the final minute, Torres and Gabriel Jesus both had goals disallowed for offside – with both having involved major mistakes from the Northern Ireland keeper.
“It was important to come back with a victory in the Premier League,” said City boss Guardiola, whose side had lost 2-0 to Tottenham in their previous league game.
“We play a lot of games so to play 90 minutes and maintain a good level is not easy, but there are always things to improve on.
“It’s important for our people to score goals and it is a chance for them to keep playing.”
Man City’s favourite opponents
With only 10 goals in their opening eight Premier League games and Sergio Aguero missing with a knee injury, it was just as well Burnley were City’s visitors on Saturday.
Guardiola’s side have dominated a number of opponents during the Spaniard’s time England, but the arrival of Sean Dyche’s Clarets at the Etihad is as near a home banker as it is possible to get.
City have now scored 27 times in six matches against Burnley on this ground and once Mahrez had broken the deadlock there was never a chance they would be thwarted.
The visitors simply could not afford the kind of error that saw central defender James Tarkowski get caught out of position close to the touchline after just six minutes, as City swept the ball across the pitch and Mahrez stepped inside to curl home.
Mahrez also has a particularly liking for Burnley – he has now scored eight times against them.
His second, another well-struck shot that curled in at the far corner, was the first time the Algeria winger had scored two in a game since the corresponding fixture last season.
When left-back Mendy smashed home a superb volley from De Bruyne’s cross, it was the first time City had scored three in the first half of a game since they hammered Liverpool in July. It was the first time they had scored three at all since their opening game of the season.
These statistics are at odds with previous campaigns, when City have almost scored at will – and Burnley could be forgiven for thinking not much has changed, especially once Torres and Mahrez had converted their second-half efforts.
Now City’s task is to show they can hurt different opposition in the same way.
A tough afternoon for Clarets
This was another chastening afternoon for Burnley, who have won just one game all season and face the very real prospect of dropping back into the bottom three before this round of fixtures is complete.
Dyche will surely be unhappy at the lapses in concentration that led to City’s first two goals and England keeper Pope needs to regain his fitness quickly given the troubles Peacock-Farrell endured.
Burnley’s other debutant, 20-year-old midfielder Josh Benson, came closest for the visitors when his second-half free-kick was deflected narrowly wide.
In truth, Benson was not in the same class as the men he was opposing – although, not for the first time in recent seasons, that could be said for every Burnley player.
“You can’t start a game with a gameplan then throw it out of the window with a mistake that early against this team,” said Dyche.
“They use the ball so well and there’s movement everywhere, so it becomes a tough afternoon.
“We have got injuries galore at the moment. We recovered then got four or five more this week. We played into their hands. We played a short pass which wasn’t needed. We wanted to put it on top of them but we didn’t do it.”
Peacock-Farrell’s unwanted record – the stats
- Manchester City have won their past seven meetings with Burnley by an aggregate score of 28-1.
- Burnley have lost seven of their past 10 Premier League games, after losing just one of their 15 before that.
- City are only the second side in Football League history to win four successive home games by five or more goals against the same opponent, after Notts County did so against Port Vale between October 1893 and February 1907.
- Only in 1888-89 have Burnley lost more of their opening nine matches of a top-flight season than the six they have this term.
- Mahrez has scored seven goals in his past four Premier League appearances against Burnley – and has netted more league goals against them (eight) than he has against any other opponent.
- Since his Premier League debut (for Chelsea in August 2013), Manchester City’s De Bruyne has provided 71 assists in the competition, eight more than any other player, despite making only three appearances across the first two campaigns in that time.
- Mendy’s first City goal came in his 60th appearance for the club.
- Torres netted his first league goal for City with his 14th shot in the competition and on his seventh appearance.
- Burnley’s Peacock-Farrell became just the third goalkeeper to concede five or more goals on their Premier League debut, after John Sheffield in 1994 (five, Swindon v Aston Villa) and Matt Murray in 2003 (five, Wolves v Blackburn).
Manchester City travel to Porto in the Champions League on Tuesday (20:00 GMT kick-off), while Burnley host Everton in the Premier League on Saturday, 5 December (12:30).