Al Sadd and Esteghlal faced each other last year in the playoff and it was Esteghlal who knocked out its opponent on penalties to reach the group stage, the-afc.com reported.
Both sides have lifted the Asian Club Championship, Al Sadd in 1989 and Esteghlal two years later. But since the inception of the AFC Champions League, Esteghlal's best performance was reaching the semifinals in 2013, while Al Sadd was the last West Asian champions, lifting the trophy in 2011.
Esteghlal dominated Group D, going unbeaten in all six games to finish top of the group, ahead of the UAE’s Al Ain, Qatar’s Al Rayyan and Saudi Arabia’s Al Hilal.
A late equalizer got Winfried Schäfer's men up to a good start away against Al Rayyan, but the highlight of the team’s group performances was doing the double against 2017 runner-up Al Hilal.
In the round of 16, Esteghlal was handed an all-Iranian affair against another Persian Gulf Pro League club Zob Ahan Isfahan. The 2010 finalist won the first leg at home through a stoppage time penalty that was converted by Georgian defender Giorgi Gvelesiani.
A week later at Azadi Stadium, Senegalese striker Mame Baba Thiam bagged a hat-trick as Esteghlal romped to a 3-1 victory to book a date with Al Sadd in the last eight.
Having replaced Thiam and Server Djeparov with Morteza Tabrizi and Humam Tariq, creative midfielder Farshid Esmaeili remains the man who makes it all tick in attack for Esteghlal.
In his fourth season at Azadi Stadium, Esmaeili has grown in importance with every passing year. His four assists and nine chances created in the 2018 AFC Champions League underline his importance to the side.
Al Sadd was drawn in Group C with Esteghlal's rival, Persepolis, and despite firing 11 goals — more than any team in the group —it only managed to finish second behind Persepolis, having lost its final group game in Tehran 0-1.
Braces from Baghdad Bounedjah in the first two games were the highlight of the group campaign as Al Sadd overcame Uzbekistan's Nasaf and Persepolis, and the Algerian got his third brace in a 2-1 win against the UAE's Al Wasl.
Even at the age of 38, midfield maestro Xavi continues to dominate the middle of the park for Al Sadd. Only two players in the competition, Oscar and Ricardo Goulart, created more chances than the Spaniard's 22.
Xavi defense-splitting passes have set up three goals, but his ball retention has been equally impressive. Only two midfielders have a higher pass accuracy than his 90 percent among those with 100 passes or more in the competition.
Esteghlal vs. Al Sadd
Venue: Azadi Stadium, Tehran
Kickoff: August 27, 20:30 UTC+4:30