From right-back to left-back to centre-back Cesar Azpilicueta has become the Premier League's most complete defender, and ahead of Chelsea's trip to West Ham United, Sky Sports' Nick Wright examines why.
It was three years ago last month that Gary Neville and Jamie Carragher first described Azpilicueta as the Premier League's best defender.
"When I watch him, he's as near to perfect as possible when it comes to defending; he's immaculate," Neville said on Sky Sports' Monday Night Football.
"You very rarely see anybody get the better of him," Carragher added. "He'd be my number one."
It seemed a big call at the time.
Azpilicueta was a largely unheralded figure in a back four which featured John Terry, Gary Cahill and Branislav Ivanovic.
But having previously established himself as first-choice right-back, he was proving just as effective on the left, keeping Ashley Cole and Filipe Luis out of the team and helping Chelsea make an unbeaten start to the season.
Three years and two Premier League titles later, Jose Mourinho's back four has become Antonio Conte's back three and Chelsea's right-footed left-back is now a brilliant centre-back.
Since August 2015, the Spaniard has started 89 league matches out of 91. Last season, the 28-year-old did not miss a single minute.
It is extraordinary that a player who had never played at centre-back just 18 months ago is now described by Conte as "one of the best in the world," but Opta's stats are convincing.
Azpilicueta has only made one error leading to an opposition shot in the last three seasons.
None of the eight defenders to have started more than 10 league matches for Chelsea in that time have made fewer.
In addition, despite standing at only 5ft 9ins, he has won more aerial duels than any other Chelsea player since the start of last season.
His full-back experience means he is an attacking weapon too. Last season he contributed four assists - more than any other centre-back in the Premier League - and he is already up to five in the new campaign.
Only David Silva, Kevin De Bruyne, Leroy Sane and Aaron Ramsey have provided more.
It may seem like a statistical quirk but it is actually the result of a deliberate strategy by Chelsea.
