It was the second good result for City on Sunday after Liverpool and Manchester United played out a goalless draw at Anfield earlier in the day. Approaching the halfway point of the season, five points separate the top six but even in a congested race, City are now the bookmakers' favourites to win a third title in four years. It is not without foundation.
Stones has scored three times in his last four games over all competitions but it's his form in front of his own goal that has helped put City in contention. Since winning back his place in November, Stones has started 11 games during which City have conceded just once. With Ruben Dias he has formed the meanest defence in the league having shipped 13 goals in 17 games, four fewer than Jose Mourinho's Tottenham and 11 fewer than leaders Manchester United.
Stones walked off at full-time wearing a wide smile but he will also be pleased that his efforts next to Dias prevented Palace from registering a single shot on target. City are now unbeaten in 15 -- having won eight in a row -- and have conceded just three goals in nearly 23 hours of football.
In a season during which City have found goals hard to come by, Guardiola will be pleased to see his team find the net four times but this still isn't the ruthless, dead-eyed, title-winning Manchester City of 2017-18 or 2018-19, and their strength, at the moment, is at the other end.
"We didn't concede, we were so stable, it is an important victory," said Guardiola. "We try to play the same way we have in the last few seasons and in the back four we don't make mistakes. Last year we made a lot.
"Last year was the worst -- before we were always solid behind, it is just individual quality. Ruben [Dias] has helped a lot. If there is one player I am more than pleased that everything is going well, it's John Stones. He is playing because he deserves it."
It is a remarkable turnaround for Stones who appeared to be on his way out in the summer. Contract talks shelved and the arrival of Dias and Nathan Ake looked to signal the end of Guardiola's patience with a player who had never really lived up to the expectation of his £47 million move from Everton in 2016. But injury-free and enjoying a more settled life away from football, Guardiola says the 26-year-old is in the best form of his career.
It says everything that Aymeric Laporte -- whose lengthy absence last season was regularly offered as a reason for Liverpool running away with the title -- has not started a league game since the defeat to Tottenham in November but has barely been missed. Stones was on the bench against Liverpool the weekend before that setback in North London but when City meet the champions at Anfield in three weeks' time, the England defender is likely to be one of the first names on Guardiola's team sheet.
So too will be Kevin De Bruyne, whose delicious cross with the outside of his right boot to set up Stones' first goal, and Raheem Sterling, who scored the fourth with a vicious free kick which arrowed into the top corner. Ilkay Gundogan, so important for Guardiola in the big games, also found the net with a wonderful effort from the edge of the box which curled inside the far post.
It was only the fourth time this season City have managed three or more goals in the league this season and, more often than not, they have found a different way to win. The clean sheet against Palace was the sixth in nine home games and their second in five days after beating Brighton 1-0 on Wednesday.
"If we can keep clean sheets we don't have to come out and score four goals every week," said Stones.
"The whole team deserve credit for how they press and stop attacks coming to us.
"It's tough when you're not playing or don't perform to your best. I went back to basics, looked at myself first, and what I could improve. I had to keep fighting and keep believing in myself, I did that, kept the faith, and kept grinding away. I'm still trying to improve."
The worry for United, Liverpool, and the rest is that City are getting better too.