Everton manager Roberto Martinez has claimed that the pairing of Phil Jagielka and John Stones is the best in the Premier League.
The duo have kept three clean sheets in six matches in the top flight, and have overall conceded five goals.
Martinez has claimed that Stones, who was the subject of four rejected bids from Chelsea in the summer, is learning from his Everton teammate.
Following Saturday's goalless draw against Swansea City, Martinez told reporters: "I don't think there is a better pair of centre-backs in the Premier League.
"When you look at John Stones and the way he performs with maturity, the reason he is allowed to play the way he does is because of the influence of Jagielka.
"They are improving and John is improving to be able to learn how to perform under the most extreme circumstances."
Only Manchester City and Tottenham Hotspur have conceded fewer goals than the Merseyside outfit.
