The reigning Premier League champions are set to meet the FA Cup holders at Wembley Stadium on Sunday with the first silverware of the season on the line.
Arsenal’s preparations for the game continue to be hindered by speculation suggesting that a prized asset could soon be heading out of north London, with ‘sick’ Sanchez being heavily linked with Manchester City and Paris Saint-Germain.
Chelsea hope that situation will work in their favour, with Courtois conceding that the Blues’ chances of emerging victorious will be greatly improved if a dangerous opponent plays no part in proceedings.
The Belgium international goalkeeper told reporters: "Alexis is a guy with a lot of quality. If you see all the games from last season there is a lot of danger coming from him.
"He has a very strong shot, he is quick. He has the technique. He is important for them but Arsenal have a lot of players with quality.
"So they will miss him but I think they have a lot of players with that quality to replace him. I think they have bought a good new striker [in Alexandre Lacazette].
"I’d prefer if he [Sanchez] doesn’t play because he is a good player! But we cannot only look to him.
"For example in the FA Cup Final [Arsenal beat Chelsea 2-1 in May] they missed some defenders and everybody thought they would be bad. But Per Mertesacker played a great game that day.
"So you cannot look to the team as one player or another player. It will be a difficult game regardless but I hope for the same outcome as the friendly last week."
Chelsea recently beat Arsenal 3-0, with Michy Batshuayi bagging a brace in a pre-season fixture in Beijing.
The Gunners were not at full strength in that contest, and have taken in several other games since then, but confidence and belief is with the Blues ahead of another London derby date.