After getting down low to keep out Davide Zappacosta in the first half, Oblak also denied Alvaro Morata on a number of occasions, most notably when the former Real Madrid forward went through on goal shortly after Chelsea equalised.
Chelsea's draw at Stamford Bridge allowed Roma to overtake Antonio Conte's team and finish top of group C on the basis of their head-to-head record.
With English teams leading four of the other seven groups, Chelsea's only possible last-16 opponents as it stands are PSG, Barca and Besiktas.
Michy Batshuayi's season may come to be defined by two moments against Atletico Madrid. But we tried to find the strength to draw and try to win.
If the Azerbaijan side are beaten, Atletico would fall into the Europa League, irrespective of the result at Chelsea.
Ex-Chelsea striker Fernando Torres was returning to Stamford Bridge on Tuesday evening
However, it does not look as though he will be available for selection against Atleti.
The42 has just published its first book, Behind The Lines, a collection of some of the year's best sports stories. "It's important to have patience and realise that mistakes will happen".
According to The Mail, the 30-year-old played no part in the Blues' training on Monday, and he is still recuperating from a persistent knee problem sustained after a nasty tackle from Manchester City's Sergio Aguero last term.
With a £77.5m buy-out clause at Atletico, Oblak would not be too costly for either clubs (especially if they bank even more for Courtois or De Gea) and the Slovenia international showed once again at Stamford Bridge that he is a world-class goalkeeper.
Chelsea are favourites to beat Atletico Madrid at 11/10.
After landing a tough group in this season's Champions League, Chelsea did wonderfully well to put themselves in a position to make their life in the last 16 a whole lot easier.