Chelsea manager Antonio Conte hailed the performances of Marcos Alonso and Victor Moses at wing-back as being key to his side's strong run of form.
The duo made vital contributions in Chelsea's 2-0 win over Southampton at St Mary's, with Moses providing the assist for Eden Hazard's opening goal.
Alonso, who Conte signed from Fiorentina in August, is an established left-back but he has proved effective in a more advanced role, while Moses has defied his reputation as a fringe player by cementing his place in Chelsea's starting line-up this season.
Conte, who has utilised a 3-4-3 formation during Chelsea's run of four consecutive Premier League victories, said: "This role is very important in this system because you must have good stamina and quality to play as a wing-back.
"I ask my wing-backs to attack and defend. I think Moses is a great surprise in this aspect because we know him as a winger but I think he is playing in a fantastic way.
"For Alonso it wasn't easy to go into the English league and to play in this way."
Conte suggested that his squad contains enough strength in depth to use wing-backs throughout the season, adding: "We have to continue but I think Pedro can also play in this role, like Moses.
"More defensively, [Branislav] Ivanovic or [Ola] Aina can play as wing-backs, but I'm pleased because I'm seeing a lot of positive things."