Chelsea were without manager Thomas Tuchel once again as he recovers from Covid-19, but had Africa Cup of Nations-winning goalkeeper Edouard Mendy available albeit on the bench.
It was the Blues who made the dominant start earlier on, with chances presented for Hakim Ziyech, Cesar Azpilicueta and Romelu Lukaku, which none utilised.
The breakthrough came two minutes from the half-hour mark when a teasing cross into the area from Kai Havertz landed onto Lukaku, who finished from a few yards out.
Hilal continued to battle the European champions and nearly conceded again a minute to halftime through a half-volley from afar by Marcos Alonso off a corner-kick, but it went wide.
After N’Golo Kante came on for Jorginho, the Blues were denied a second goal through a delicate attempt from close-range by Havertz but he clattered the upright.
Hilal’s first chance in anger followed five minutes after the restart off a speculative strike from range by Mohamed Kanno, but the attempt clipped the top of the crossbar before flying out.
The Blues carved out another clear chance inside the 60th minute through a curling attempt from the right of the area by Ziyech, but goalkeeper Al Maiouf made a fine stop.
Hilal regained advantage after three minutes off a clear one-on-one by Moussa Marega following a through pass by Matheus Pereira, but Kepa Arrizabalaga saved.
With the match headed to the closing passages, there were chances that popped up at either end but the Blues emerged winners in the end and will play Palmeiras in the final on Sunday.