Plenty of matches may be billed as the irresistible force against the immovable object. Given the record-breaking personnel involved, perhaps Chelsea against Manchester United on Sunday actually is. In the red corner, Cristiano Ronaldo, bidding to become the first footballer ever to score 800 competitive goals. The Portuguese’s strike against Villarreal took him to 799 for clubs and country. The fact that only one has come in his last six Premier League games is an indication of the problems that brought the sacking of Ole Gunnar Solskjaer. But as his opportunistic lob in Spain showed, Ronaldo is not the highest scorer in the histories of Portugal, Real Madrid, the Champions League and international football for nothing. In the blue corner, a collective where the faces change but the commitment to keeping clean sheets does not. The Chelsea defence can feature Thiago Silva, the only outfield player in this season’s Premier League who is older than Ronaldo, and the rookie Trevoh Chalobah. They specialise in shutouts: 31 in Thomas Tuchel’s first 50 games in charge, when just 24 goals were conceded, which is a record for a manager at any English club. It is an indication of how parsimonious Chelsea are that Juventus’ Wojciech Szczesny has conceded more goals at Stamford Bridge this season than Edouard Mendy. If the damning statistic for United is that they have let in as many league goals as Chelsea, Liverpool and Manchester City have between them, it is partly because of the astonishing frugality of Tuchel’s team. These are early days but they are on course to break a top-flight record set by a defensive strategist who managed both clubs: Jose Mourinho’s 2004-05 Chelsea side were only breached 15 times. Last season, everyone conceded at least twice as many. When Frank Lampard was sacked in January, Chelsea had let in more than Burnley. If the subsequent 10 months highlight the brilliance of Tuchel’s coaching, the effectiveness of his 3-4-3 formation, the ease with which he has swapped players in and out and the excellence of the rejuvenated Antonio Rudiger, it may offer United hope that they, with the third worst defensive record, can effect a similar transformation under new management. The figures nevertheless suggest Chelsea’s defensive record is flattering. They have allowed opponents 34 shots on target to City’s 15. Their expected goals, reflecting the calibre of chances teams have, suggest they should have conceded 11 goals, not four. It is also a sign of Mendy’s magnificent form, and having a superb goalkeeper, much like having a virtuoso goalscorer, is a perfectly legitimate way to win the numbers game. United’s caretaker manager Michael Carrick may have introduced an element of uncertainty to Tuchel’s planning. Ronaldo started on the left against Villarreal. It makes the role of Chelsea’s right-sided centre-back still more important. It has been filled in the last two games by Chalobah, the 22-year-old who was loaned out to Lorient last season and who scored his first Champions League goal in the rout of Juventus but Cesar Azpilicueta or Andreas Christensen offer more experienced alternatives. Tuchel has proved adept at selecting the right players for the right games. That task has become harder with Ben Chilwell sustaining a cruciate ligament injury when he was in the form of his life. But, while Romelu Lukaku could make his comeback against his old club, Tuchel has rendered the £98 million man less important by turning his defenders into a bunch of budding Ronaldos. Chelsea’s wing-backs have scored nine goals this season, their centre-backs a further seven. Reece James has scored as many as Chelsea have conceded in both the Premier League (four) and the Champions League (one). If Ronaldo can be painted as the selfish scorer, the player who contributes little else, the Chelsea defence are the selfless scorers. Over the Portuguese’s extraordinary career, no one can rival his record. This season, James has as many Premier League goals. It is a reason why Chelsea and United sit first and eighth.