The Italian revealed that Morata has a back injury, having been suspended for the 4-0 win at Brighton and Hove Albion on Saturday, while Fabregas is still struggling with a hamstring problem.
“Morata and Fabregas are out,” Conte said. “They are not available for the Arsenal game. Then we have to check a couple of situations. But, for sure, Morata and Fabregas are out.
“He [Morata] has a problem in his back, and he's injured. As I said before, I have to check a couple of situations before making the best decision for tomorrow's game.”
Conte meanwhile confirmed that Andreas Christensen is available. “He is fit. He trained with us and is fit.”
The tie with Arsenal is currently at 0-0, meaning it could well go to extra-time and away goals.
READ MORE: Wenger confirms Aubameyang talks
READ MORE: Kenedy travels to Newcastle for medical
“I must be honest, I think we start 50:50,” Conte said of his side’s chances. “If we score, we have a little advantage but, at the same time, they have a big advantage playing in their own stadium. So we both have the same chance of going through.
“Last season, we saw two different games [against Arsenal]. The first game was a disaster for us, because we lost 3-0 after 30 minutes. After that game, I think we changed a lot of things for us. Then, in the second game at home, we won 3-1 because [Olivier] Giroud scored on 92 minutes.
"Otherwise it would have finished 3-0 like in the first game. This season, the first game in the league finished 0-0, 2-2 in the second game. We are showing to be of the same qualities. Two teams with the same values.
"When you play a lot of times and the final result is always in the balance, it means the teams are very close. Tomorrow, there is not another game after. We don't have another possibility. We have to try to reach the final like Arsenal.”