Everton travel to Stamford Bridge on Saturday as the latest team to try and beat Chelsea and Thibaut Courtois.
Antonio Conte's side have gone 410 minutes without conceding a goal, but are the Toffees the team to end Chelsea's clean sheet run and deny them a fifth successive league win?
Everton a test of Chelsea's title credentials
Following Chelsea's 3-0 defeat at Arsenal at the end of September, Antonio Conte adopted the 3-4-3 formation he favoured during his time in charge of Juventus and the Italian national team. His side are proving to be the real deal since they changed formation; four successive Premier League wins in October has catapulted Conte's side to fourth place in the table, just one point behind leaders Manchester City.
Chelsea conceded nine goals in their first six league games, but following the shift to a three man defence, which becomes five when the other team have the ball, Thibaut Courtois has yet to be beaten. The Belgian has kept out the likes of Manchester United, Leicester City and Southampton during that spell - the first time they have kept four clean sheets since August 2010.
Everton will be the latest test of Chelsea's title credentials, but Conte will have set his team the objective not only of beating Ronald Koeman's side to keep last month's momentum going, but also keeping another clean sheet.
Can Lukaku be the man to finally beat Courtois?
One player that will be motivated above and beyond his teammates to end Chelsea's winning streak is striker Romelu Lukaku. Discarded by former Blues boss Jose Mourinho, there had been plenty of rumours linking the Belgian with a move back to Stamford Bridge this summer.
Lukaku poses the biggest threat to Chelsea and Courtois in a game that will see the league's two top scorers go head-to-head. The match pits Lukaku against Diego Costa, who leads everyone else in the division with eight goals from his 10 appearances to date. However, Lukaku is not far behind.
The Belgian is second in the Premier League leading goalscorers' chart for the 2016/17 season; scoring seven goals in nine appearances this season (joint with Sergio Aguero). The 23-year-old will be hoping to add to that tally against the team which signed him, sold him and failed to bring him back.
Will Chelsea's home advantage be key?
Home comforts could be the difference for Chelsea as the hosts are unbeaten in their last 21 home Premier League games against Everton since a 1-0 loss in November 1994 (W11, D10). It represents Everton's longest run of away games without a win against another club in the Premier League. Only against Leeds United (36) have they had a longer away run without a win in league history.
The Toffees did come close to ending that unwanted record in the corresponding fixture last season, but John Terry's controversial 98th-minute goal (the latest goal recorded in the Premier League last season) rescued a point for Chelsea. Last season's 3-3 draw sees Everton travel to London looking for their first league win at Stamford Bridge for 22 years.
Who will replace Idrissa Gueye in midfield?
Everton will be without the suspended Idrissa Gueye against Chelsea for the first time this season after the influential midfielder picked up his fifth booking of the campaign in last weekend's 2-0 win over West Ham.
The midfielder signed from Aston Villa in the summer and he has been one of Everton's most important players this season. No Premier League midfielder has won as many duels as Gueye, nor have they completed as many tackles as the Senegal international or won as high a percentage of their total challenges.
Given the injuries to James McCarthy, Muhamed Besic and Darron Gibson, Tom Cleverley is the obvious option to replace Gueye, but Ronald Koeman may change the Blues' formation completely in the midfielder's absence.