Defending champions Wydad Casablanca of Morocco and Horoya have four points each after two rounds and Sundowns two with the top two finishers qualifying for the quarter-finals.
Pointless Port of Togo, who defied the odds to make the last 16, appear out of contention having suffered two losses.
Horoya and Wydad meet twice when the elite African club competition resumes in July while 2016 champions Sundowns will be looking for six points when they play Port home and away.
The Guineans, competing in the group phase for the first time, will be disappointed that they had to rely on a goal by captain Aboubacar Camara on 83 minutes to salvage a draw.
They were superior in the first half of a match staged in 33 celsius (92 fahrenheit) heat and should have been ahead by the end of a goalless opening half.
Lethargic Sundowns were uncomfortable on the hard national stadium surface in Conakry and fell behind on 51 minutes when Ghana-born Ocansey Mandela converted a low cross.
After Horoya came close to increasing their lead, the rattled South Africans stirred themselves entering the final quarter and scored twice within 10 minutes to grab the lead.
Zimbabwean Khama Billiat levelled with a close-range shot on 69 minutes after being set up by Percy Tau, Sundowns’ outstanding player during the past 12 months.
Billiat was playing his last match for Sundowns before joining a new club, possibly in Azerbaijan, after six years with the Pretoria outfit.
Uruguayan Gaston Sirino put the visitors ahead from the penalty spot with 11 minutes remaining after Horoya goalkeeper Khadim Ndiaye smashed into Billiat.
But just as Sundowns looked like achieving an undeserved victory, Camara nodded a corner past Ghana-born goalkeeper Brimah Razak to equalise.
The match, originally scheduled for last Tuesday, was delayed so Sundowns could host Spanish league and cup winners Barcelona in a Soweto friendly.
Horoya and Sundowns are among 16 clubs chasing a $2.5 million (2.1 mn euros) first prize and qualification for the 2018 FIFA Club World Cup in the United Arab Emirates.
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