The Blues top the league and have been flying all season since Italian boss Antonio Conte found the players to fit his system. They have lost only three matches all term, picking up 18 wins and two draws across their other 20 matches.
Arsenal, who sit in third place - nine points behind the leaders - have won 14, drawn five, and lost four of their opening 23 games.
With 15 league matches remaining for every Premier League side, it's beginning to get to the business end of the season.
All of the top six sides bar Manchester City dropped points in their midweek matches, missing the opportunity to capitalise on Chelsea's 1-1 draw with Liverpool.
Chelsea now have the chance to go 12 points clear at the top of the league should they win the weekend's early kick-off, and Arsenal face a massive task to beat the league leaders.
Football is a team game, and there's no doubt that the two teams have had a huge effort from their whole squads to be in such positions at this stage in the season. Nonetheless, Diego Costa and Alexis Sanchez have had a hand on the wheel as the driving force for their respective sides, and they could well be the difference this Saturday.
Using data courtesy of EA Sports, we've been able to find out who has been more influential out of the duo so far this season.
Both Costa and Sanchez have scored 15 goals for their teams this season, with very little to split the two as to how regularly they bag: Costa once every 124 minutes, Sanchez every 131 minutes.
Despite playing out wide, Sanchez clearly holds just as big a goalscoring threat as his Spanish opponent Costa. The main difference is that the Chilean forward is much more influential on his team's overall game.
While Costa has provided five assists for his Chelsea teammates, Sanchez has supplied eight for the Gunners. The Arsenal man has completed 737 passes - significantly more than Costa's 451 - and the vast majority of those have come in the opposition half (613).
The stats reflect the two players' influence well. Sanchez has created 60 chances this season, more than double that of Costa who has created 28. Likewise, from wide positions, Sanchez dominates the stats, completing 13 crosses to Costa's underwhelming one.
Costa has managed a total of 147 touches in the opposition box this season, which no doubt leaves Chelsea wondering how to stop Sanchez from his wide position, as he's managed a total of 174. Costa is the more clinical of the two, with a shot-to-goal ratio of 23.77% compared to Sanchez's 17.65%.
Finally, having completed 63 dribbles so far with a success rate of 65.63%, Sanchez is clearly more capable of beating his man compared to Costa who has completed 40 with a success rate of 40.41%.
On paper, stats suggest it will be one of these two men who will likely be the difference in the weekend's biggest match.
While Arsenal know that Sanchez can create an opportunity from out of nothing, for himself or his teammates, they must be aware that the clinical Diego Costa is certain to finish at least one in four chances when they fall his way.
Arsenal will be hoping that Sanchez can lead them to victory on what is usually unhappy hunting grounds for the away side, while Chelsea will look to continue their remarkable home form and look to Diego Costa to take them 12 points clear.
Data Courtesy of EA SPORTS, the Lead Partner of the Premier League.News Now - Sport News