Asian football officials may be forced to tally yellow and red cards or even hold a special lottery to decide the last 16 as an ultra-competitive AFC Champions League group phase goes down to the wire.
With eight knock-out berths still available, 16 teams are in the running, setting up a mad dash for the line in the final group games on Tuesday and Wednesday.
Group C is the only pool where both qualifying berths, and top spot, have been decided. In Group B, both spots are still available and all four teams - Lekhwiya, Pakhtakor, Al Ettifaq or Al Shabab Al Arabi - could finish top.
And in Group E, Buriram United's campaign to become the first Thai team to qualify may be decided by a count of yellow and red cards, or even a specially convened lottery.
With Buriram and Vegalta Sendai tied on points, head-to-head record, goal difference and goals scored, if both teams win or draw they may be relying on their disciplinary record to clinch second spot behind group winners FC Seoul.
And should Japan's Sendai, on seven yellow cards compared to Buriram's 15 yellows and one red, suffer a meltdown against Jiangsu Sainty, qualification could be decided by a lottery at AFC headquarters in Kuala Lumpur.
All to play for
Buriram coach Attaphol Puspakom, still smarting from Sendai's injury-time equaliser which denied his team qualification last week, urged his players to maintain their belief when they take on group winners FC Seoul on Wednesday.
"It will certainly be a hard game for us, but we have to keep the faith," he said.
Elsewhere, China's Guangzhou Evergrande are already through but their bid to finish top of Group F, and secure a potentially easier last-16 draw, has been hampered by a touchline ban for their coach Marcello Lippi.
Lippi, who led Italy to the 2006 World Cup and also won the 1996 European Champions League with Juventus, was sent to the stands during last week's 3-2 defeat to Urawa Red Diamonds for kicking a water bottle.
Lippi and defender Zhang Linpeng, who was red-carded, are both banned for Wednesday's clash with Jeonbuk Hyundai Motors and they will remain suspended until their disciplinary cases are decided, an AFC official told AFP.
Meanwhile, newly crowned Australian champions the Central Coast Mariners will reach the knock-out phase for the first time if they beat Japan's Kashiwa Reysol on Tuesday, or if Group H's other result goes their way.
"One of our main goals before the season started was to advance from the group stage of the ACL, and now we've got the chance to do that," skipper John Hutchinson said.
"We've got a great record at home, and we'll be playing to win that game on Tuesday."
The two-legged round of 16 starts on May 14 and ends the following week.
The competition then takes a break before resuming for the quarter-finals in August.