Manchester City manager Manuel Pellegrini said Joe Hart must keep improving if he is to become the best goalkeeper in the world.
Hart produced possibly the save of the season in City's 4-2 Premier League win at Swansea, his flying one-handed stop preventing Federico Fernandez's 82nd-minute header from making it 3-3.
The England goalkeeper made another point-blank save from Bafetimbi Gomis two minutes later before Swansea old boy Wilfried Bony, on as a late substitute, settled matters in injury time with only his second City goal.
"It was a beautiful save in a very important moment," Pellegrini said after his side had tightened their grip on second spot with a fifth consecutive league victory.
"Joe is the No. 1 goalkeeper in England and I think he has improved a lot this season.
"Bringing Willy Caballero was good for him, giving him good competition and also working with the goalkeeping coach Xabier Mancisidor.
"It's important for him but he most important thing is he has an open mind. He is only 28 years old and he must improve in a lot of things, but he is working hard to do it.
"It is difficult for a young goalkeeper to be so good at the start of his career and it is difficult to compare him with all the other goalkeepers here.
"There are three or four good goalkeepers in this league, but Joe must improve and not think he knows everything at this moment. Every day he works hard."
James Milner scored City's second goal and gave another performance full of endeavour and commitment, even though he is out of contract at the end of the season and he may move on this summer.
Pellegrini stressed he wants Milner to stay at the Etihad Stadium but he admitted the final decision rests with the player himself.
"It's a decision James must take at the end of season, what is better for his future," Pellegrini said.
"I always talk that he is an important player for our team. He can play in different positions because he is an intelligent player.
"He always gives 100 percent but it will be sorted at the end of the season. I can think [staying at Manchester City] is best him for him but it's important what he thinks."
Asked if he wanted to keep Milner, Pellegrini replied: "Yes, of course. He is a very important player for us."
