Sergio Reguilon will be key to Jose Mourinho beating his former employer Chelsea when Tottenham Hotspur visit Stamford Bridge for Sunday’s London derby.

Reguilon has been a favourite for Mourinho since signing the Spain international from Real Madrid for £32million this summer, with the defender starting five of Spurs’ last seven top-flight fixtures.

Mourinho has seen the 23-year-old record two assists, as well, with Reguilon teeing Harry Kane up to score at home to West Ham United and Gareth Bale to net in this month’s 2-1 win over Brighton and Hove Albion.

Reguilon had his work cut out to help Spurs better Manchester City in north London last weekend as Pep Guardiola’s Citizens ran riot but with no end product, as the defender was forced into 10 duels and making three clearances, three successful tackles, an interception and blocking one shot, per SofaScore.

He won five of his eight ground battles and once in the air, showing the £48,077-per-week gem’s abilities at the back are as strong as former Spain coach Robert Moreno once lauded him for being in attack.

“He has so much power and when he goes forward, he is unstoppable. He oozes energy and he reminds me of when Dani Carvajal was starting out,” Moreno said, via quotes by BBC Sport.

Mourinho will need to rely on Reguilon being as strong in defence against Chelsea this weekend as he was at home to Manchester City, with Frank Lampard’s Stamford Bridge natives prone to favour attacking moves on their right-hand channel.

Chelsea ranked joint-fourth in the Premier League for attacking moves on their right-flank this term heading into matchday 10, with only Sheffield United (42%), Wolverhampton Wanderers (42%) and Leeds (39%) more one-sided than the Blues (38%), per WhoScored.

Lampard’s men fell to 15th in the top-flight for attacking moves on the left-hand side of the field (37%) and were one of six clubs who focused a quarter of their attacks through the middle of the pitch.

Their preference to attack the zone Reguilon will occupy rises to 39% when playing at home, too, ditching central attacks (23%) more often while remaining at 37% on the left.

Another top-draw defensive display from Reguilon on Sunday will be what Mourinho needs to win against his former employer and record only Spurs’ second top-flight win at Stamford Bridge since February 1990.

AND in other news, Spurs are in the hunt for a gem who “can do everything” and might not cost Daniel Levy a penny.