It wouldn't be surprising if Chelsea manager Antonio Conte has once again had a few of his fabled sleepless nights over the course of the international break.
When the Blues hit the skids in September, losing successive Premier League games against Liverpool and Arsenal, Conte mused that after a defeat it was normal for him not to sleep for a couple of nights as he reflected on what had gone wrong. This time around, it isn't Chelsea's results that will be keeping Conte awake, it's the terrifying prospect of being without the services of Eden Hazard and Diego Costa when Chelsea return to top-flight action on Sunday against Middlesbrough.
Having scored in Sunday night's 8-1 demolition of Estonia, Belgium captain Hazard asked to be replaced with 17 minutes remaining of the World Cup qualifier. Hazard, 25, came off following a challenge by Gert Kams in which the Estonia defender appeared to tread heavily on his ankle. Although the substitution appeared precautionary, Hazard will likely find himself on the Chelsea doctor's treatment table when he returns to Stamford Bridge.
While Hazard played twice for Belgium in the past week, his club teammate Costa hasn't featured for his adopted country Spain. A groin injury sustained in Chelsea's 5-0 victory over Everton has proved more problematic than first thought when the striker excused himself from Spain's initial training sessions prior to their World Cup qualifier with Macedonia.
During his period of sleepless contemplation following the loss to Arsenal, Conte not only figured out the cause of Chelsea's woes, but remedied them as well. Since that 3-0 defeat at the Emirates, Chelsea have gone on a winning streak that currently stands at five games -- a sequence of results which has catapulted them into the ranks of serious title contenders.
While Chelsea's stellar renaissance can rightly be referred to as a team effort, there is no doubting the fact that Hazard (seven goals and three assists) and Costa (nine goals and three assists) have been pivotal to this success. After what can politely be described as a fallow season last term, the duo have recaptured the form which turbo-charged the Blues to Premier League glory in 2015 and Conte need only look to last month's EFL Cup defeat against West Ham to confirm their essential status when it comes to team selection.
Conte opted to rest Hazard and Costa from his starting XI at the London Stadium and although both players saw action in the game, West Ham were already two goals to the good and in no mood to roll over once Chelsea's high profile stars entered the fray.
Much is made about depth of Chelsea's squad, however the Blues came up short against West Ham despite Conte deploying the same 3-4-3 system which he switched to successfully following the Arsenal debacle. Yes, a re-jigged defence was at fault in conceding the goals that confirmed defeat and a cup exit, but Oscar and Michy Batshuayi who came in for Hazard and Costa were not at the same incisive level their teammates have reached this season.
Simply speaking, Chelsea are nowhere near the potent threat they have proved themselves to be without Hazard and Costa in their ranks. The international break may have halted the team's free-scoring momentum, but that should be regained provided Conte can field the two players who have accounted for 16 of his side's 26 Premier League goals between them so far this season. Nervous times, then, for the Italian, who will be relying on Chelsea's medical team to ensure he has a good night's sleep as the clock ticks down to Sunday.