Pep Guardiola has backed Manchester City defender John Stones to learn from his mistakes if he accepts they are an integral part of the game.
Stones made a crucial error which led to a goal in England's Nations League semi-final defeat to the Netherlands in Portugal in June.
He has also faced criticism for some performances in a City shirt but with the club having been linked with a summer move for Leicester centre-back Harry Maguire, Guardiola has come to the defence of Stones.
"John is a young player who has made mistakes once or twice but not too many," he said ahead of their pre-season friendly against Yokohama on Saturday.
"This kind of situation, if the player is open-minded, you become stronger. It's part of the game.
"People always hear just wins, no defeats and no mistakes. In football, there are more mistakes than success and you lose more than you win.
"If he makes it part of his process to push himself to make himself better, he will do it. But it depends on him."
Guardiola refused to be drawn when asked if City would be making any further signings in the current transfer window, including when asked specifically about Brazil right-back Dani Alves, who is a free agent after leaving Paris Saint-Germain.
But he conceded there may be some scope to further add to his squad as they look to win the Champions League to add to their recent dominance in domestic football.
"No, not many. I like the faces that we have," he added when asked about possible transfer business.
"Maybe but the transfer market is so difficult and the team is good enough. Maybe zero, maybe one, maybe one and a half."
Guardiola was joined by midfielder Phil Foden at the pre-match news conference and he lavished praise on a player who is gradually being brought into the side on a more regular basis.
Viewed as a long-term replacement for the experienced David Silva, who is set to leave City at the end of this season, Foden came off the bench in the 6-1 win over Kitchee on Wednesday.
"He (Foden) is the most talented player I have ever seen. His problem is sometimes his manager doesn't put him in the starting XI," said Guardiola.
"He deserves all the minutes but with his competitors, it isn't easy. He works incredibly. He knows I'm here to help him."