Thomas Tutchell's full-back helped Chelsea shine on both ends of the road

Chelsea had the best defensive record, but full-backs Rees James and Ben Chilwell also proved devastating in the opposing half. Let's take a look at how Thomas Tuchel's system sets the standard in the Premier League.

Reece James and Ben Chierwell are in good form as full-backs for Chelsea and England

Antonio Conte is back in the Premier League and he has wasted little time installing his favourite three-man defence at Tottenham Hotspur. Manchester United, Brentford, Wolves and Newcastle also used this formation in the last round of the league, and the formation is firmly revived.

But it's at Conte's former club Chelsea, where the system is currently the most flexible.

This is Thomas Tutchell's response to the new club's defensive weaknesses when he arrived in west London in January, and the results were remarkable. Chelsea's backline has become a despicable machine, scoring 19 goals conceded in the last 30 games of the season.

This semester, they are still very difficult to break down. At times, goalkeeper Eduard Mendy was busier than Tutchell hoped, but the raw data showed they had conceded just four times in 11 Premier League games, the best record in the division.

Antonio Rudiger, Andreas Christensen and Thiago Silva – Chelsea's three-back in the last two Premier League games – felt like a perfect blend, while César Azpilicueta and Trevo Chaloba both excelled when called up in that area of the pitch.

But Chelsea are also the second-largest scorers, and the attacking opportunities presented by Tuchel's change in this formation have caught the attention of recent weeks. In particular, full-backs Reece James and Ben Chirwell form.

England boss Gareth Southgate described the duo as "the key to this system" before helping his side - built in a similar way - on Friday night to beat Albania, and it was clear that the national team boss would benefit from the two players becoming difficult for experts in these areas to master.

After rejuvenated Marcos Alonso made threats from left-wing defenders earlier this season, James and Chilwell have played the last three Premier League games together.

Chilwell scored four goals in five games for club and national teams last month, while James - who is enjoying a very good season - have scored three goals and two assists in the last five games alone, including a double against Newcastle.

"He shoots like a horse," Tuchel said with a laugh after that game as he explained why James didn't need specific shooting practice. But it's almost certain that the frequency with which James and Chilwell enter the box is problematic.

Of the Premier League players who have played at least 450 minutes in a possible 990-minute game this season, James and Chilwell have touched the ball on average in the opposing penalty area than any other defender.

Notably, James' total of 26 touches in the opposing box was just two fewer than Joao Cancelo and three fewer than Aston Villa's Mattikas – and the top two on that metric have played more than twice as long this season, with a ban and ankle injury limiting the Englander's playing time.

Striking a balance between offensive threats and the required defensive work is not easy, both tactically and physically. For example, in the last two Chelsea games, any player on Chilwelby's pitch has covered more pitches or recorded more sprints, and regained possession or completed more clearances than his teammates.

"We have high demands on full-backs," Tuchel explained in an exclusive interview earlier this season. "They need to defend when that's defensive, they need to attack when we get into the opposition's penalty area.

"It's very demanding for the body, but we need them because – as simple as possible – if there is no one on the wing, we won't be in danger at half-time, and if you don't, you won't be dangerous on the wing and there will be players at half-time.

"You need to have the option to expand your defenses."

But for James and Chilwell, it's not just about plowing up and down the flanks to provide that width.

Their teammates can open up space in the interior and then have a certain amount of freedom in the final third to get James and Chilwell inside. James found those moments in Newcastle and took advantage of the capital.

"Reese was allowed in, it wasn't a problem," Tutchell said after the game. "We want to attack all the space, we have all the players in the space where we want to be dangerous. So if there are wingers waiting on the flanks, full-backs can attack the half.

"We need full-backs to go into the box to increase scoring chances and create scoring chances.

"It's a complicated game and if Callum Hudson-Odoi doesn't carry the ball and opens up space [in the preparation stages of his first goal], I don't think Reese can score. Sometimes our strikers sacrifice space. ”

For Tuchel, finding the right combination in the middle of the park this season has not been an easy task.

His early plans made Havertz and Mason Mount look promising as romelu Lukaku's auxiliary strikers, but waste and injuries forced Tuchel to regroup the trio alongside Hakim Ziyech, Timo Werner and Christian Pulisic into a different attacking model.

The return of Ross Barkley and Ruben Loftus-Cheek on the edge, while credited to the personalities of both players, is another hint that Tuchel has yet to fully identify his preferred candidate in the offensive zone.

But there is no doubt that the full-back is now providing him with a reliable service. They are also setting the standard for how the system can be used in the Premier League.

Conte's Tottenham Hotspur arrived at Chelsea on 23 January, three days before Tuchel's inauguration anniversary.

The German's full-back approach has already led Chelsea to a Champions League victory, when they are likely to be on the verge of winning the Premier League – five seasons before Conte's own triumph in stamford Bridge's system.