And with only two rounds of fixtures remaining in the group stages, matchday five is going to prove pivotal for a number of teams.
Group C Who can qualify as runners-up from Group C?
Here's a complete look at the things that can be decided in the competition this week.
Kylian Mbappe and Pablo Sarabia struck late to steal a 2-2 draw for Paris Saint-Germain at Real Madrid in a pulsating Champions League encounter that ensures the Parisiens top Group A.
The Colchoneros, however, control their own destiny and can be sure of qualifying if they beat Lokomotiv in the final group match at Madrid's Wanda Metropolitano.
Jose Mourinho managed his first home game as Tottenham manager and it wasn't without its drama as he saw his new side turnaround a two-goal deficit to qualify for the next stage. Bayern Munich were in thier element, pumping six goals past Red Star Belgrade while Tottenham Hotspur staged a comeback against Olympiacos.
On a special night for the "Special One", he will be hoping for a strong showing from his men. At the same time, he is the second player in this league after Leonel Messi of Barcelona to score four goals twice.
Shakhtar, meanwhile, can go through if they defeat Guardiola's side and Dinamo Zagrab lose.
Jose Mourinho celebrates with Harry Kane after Tottenham Hotspur came from two down to beat Olympiakos 4-2 in the Champions League on the new coach's home debut.
Three European giants and only two can qualify.
It means PSG will go through as group winners while Madrid are guaranteed to finish second after Club Brugge drew 1-1 at Galatasaray in the early kick-off.
If Dortmund (7 points) lose tonight against Barca, they have to beat Slavia Prague next to make it through.
In the other early kick-off on Tuesday, Bayer Leverkusen kept alive their chances of reaching the last 16 thanks to a 2-0 win away to Lokomotiv Moscow in Russian Federation.
Group F leaders Barcelona were held to a frustrating draw away at Dortmund on Match Day 1.
Here it is, the final group. Bayern's big win in Zagreb made it five wins from five in the group, and continued interim coach Hansi Flick's winning start in four games since taking over from the fired Niko Kovac. Ajax, Chelsea and Valencia are all on seven points and are in fray.