Al Nassr is in, Al Sadd is on the brink: Four spots up for grabs in AFC Champions League

There is just one day of matches left in the 2021 AFC Champions League West group stages, but stakes are still high for clubs in four of the five pools.

The new format implemented this season expanded the tournament from 32 to 40 clubs. Instead of the top two teams from each group getting guaranteed passages to Round of 16 in previous editions, this year's ACL only ensures knockout berths for the five group toppers and three best second-placed teams. Teams vying to progress as group runners-up will have to wait until the conclusion of the final matchday to know their fate in the competition.

On Thursday, Al Nassr FC defeated Qatari champions Al Sadd SC 2-1 in a game that decided the Group D winners and left Xavi Hernandez's men second in a perilous position with 10 points. In Group E runners-up Al Wahda FC secured their knockout-round berth as a 2-0 win against hosts FC Goa increased their tally to 13, which will guarantee them a place as one of the three best-placed second-placed teams.

Group B runners-up Tractor SC are also in the mix to progress as one of the three best second-placed teams after a 2-0 win over Sharjah FC, who had already qualified as group winners.

Still more big guns are at the risk of getting eliminated from the competition at its very first hurdle on Friday. Al Ahli SFC, Esteghlal FC and Al Duhail SC are locked in a nail-biting three-horse race in Group C while 2019 champions Al Hilal SFC will need help to advance in Group A.

Here is a look at Friday's matches that will decide the Round of 16 line up of the 2021 AFC Champions League West.

Nothing to separate Al Ahli, Esteghlal and Al Duhail in Group C

Already-eliminated Al Shorta SC's upset win over Al Duhail SC and a draw between Al Ahli SFC and Esteghlal FC on Matchday 5 means that there are three teams with eight points each atop Group C.

It is Iran's Esteghlal who top the group with more head-to-head points and a better goal differntial, while Qatar Stars League side Al Duhail are second followed by hosts Al Ahli at third. Esteghlal will face neighbours Al Shorta, who are fresh from their first win in ACL 2021, on the sixth matchday while Al Ahli and Al Duhail face off.

The three teams, which share four Asian continental titles between them, will be engaged in a fascinating battle that could swing in anybody's favour. Neutral fans will, without a doubt, be treated to 180 minutes of exciting football at the King Abdullah Sports City in Jeddah. Supporters, meanwhile, will be nowhere but at the edge of their seats.

Debutants Istiklol have 2019 champions Al Hilal sweating in Group A

It has been a fairytale debut season for Tajikistan's FC Istiklol in the AFC Champions League as they top Group A heading into the final group ties. Their remarkable run has come at the cost of Saudi Professional League champions Al Hilal SFC who find themselves second in the pool.

Though both the teams have now collected 10 points after wins in the fifth matchday, it is Istikol who top the group by the virtue of scoring more goals against Al Hilal in their two meetings. The Saudis must now win against UAE's Shabab Al Ahli Club and also hope that the Tajiks slip up against FC AGMK to go through as group winners.

A stalemate might not necessarily spell disaster for the three-time Asian champions, but they could run the risk of getting knocked out on goal difference among the second-placed teams if they fail to collect full points against the Emiratis come Friday.