Manchester City manager Pep Guardiola insisted there was still room for improvement from Raheem Sterling after the forward’s astonishing performance in a 6-1 win over Southampton that returned his team to the top of the Premier League.

The defending champions remain on course to better last season’s record-breaking tally of 106 goals after another emphatic display that leaves them with a plus-29 goal difference just 11 games into the new campaign.

Sterling was the pick of the attacking talents during Sunday’s match at the Etihad Stadium, scoring two goals and providing three assists as City raced into a 3-0 lead inside 18 minutes.

“He is a top player but still he is so young to be considered the world’s best,” said Guardiola when asked to rank Sterling among the game’s current leading players.

“He is in incredible form, he is sharp, fast, clever, fighting, decisive, he can play both sides and can play in the middle and receive the ball between the lines and commit the centre-banks with a lot of aggression.

His performance means Sterling has now been directly involved in 40 league goals – scoring 24 times and making 16 assists – since the start of last season, and Sunday’s was a timely individual display given that the 23-year-old England forward this week agreed a new five-year contract with the club, worth a reported £300,000 a week.

“It was an incredible performance but still with the young guys like him and Leroy [Sane] I would feel he can improve,” added Guardiola.

“Still, he loses simple balls, like the Tottenham game when he made an amazing assist in the first few minutes but then lost a lot of balls.”

Sarri sees Morata potential

Wesley Hoedt turned Sane’s sixth-minute cross into his own goal before Sterling laid on the first of his assists, crossing for Sergio Aguero to claim the 150th Premier League goal of his career – putting the Argentine equal-eighth with Michael Owen in the division’s all-time goalscoring list.

Meanwhile, Chelsea manager Maurizio Sarri believes a maturing Alvaro Morata can be the free-scoring striker his side needs after scoring twice in Sunday’s 3-1 win over Crystal Palace.

However, the Italian called on Morata to keep improving physically, mentally and technically if his goals are to help Chelsea keep pace with Premier League leaders Manchester City.

After a fast start to his Chelsea career after a then club record £60 million move from Real Madrid last year, Morata had scored just twice in 20 Premier League games before netting in last month’s 3-0 win at Southampton.

But he now has four goals in as many league games after two fine finishes to twice give Chelsea the lead either side of half-time before Pedro Rodriguez sealed the three points to take Sarri’s men above Liverpool into second, two points behind City.

“He is a little bit fragile from the mental point of view, but he is very young I think he can improve very fast,” said Sarri.

“I think also Alvaro has a very great potential, physical potential, technical potential, so he has to improve more.”

Morata even had the chance for a hat-trick when put clean through by Eden Hazard in stoppage time, but failed to fool Palace goalkeeper Wayne Hennessey with his attempted chip.

“I can score a hat-trick so it was not the perfect day but we will take the three points,” said Morata. “When you have a bad period, it takes long to recover.

“Last year was difficult for me for many things. You don’t expect an injury but now I am good, it is nice to be scoring.”

Hazard was only fit enough for a place on the bench on his return from a back injury and his creative spark was badly missed as Chelsea laboured until his introduction just after the hour mark.

“I think it was really very important to have him on the bench,” added Sarri. “We were lucky because immediately, in the first minute, I think he was able to change our match.

“Hazard is Hazard, he is able to do it very often.”