Al Nassr made back-to-back appearances in 2015 and 2016 but failed to progress beyond the group stage, while the Riyadh side’s best ever performance came in their only other appearance, when they reached the Round of 16 in 2011 before elimination to the Islamic Republic of Iran’s Zobahan.

The side are having a superb season domestically, meanwhile, and currently sit second in the Saudi Pro League behind city rivals Al Hilal after defeating Al Ahli 2-1 away from home in their last league outing.

Shandong have made the group stage of the tournament eight times, with their last appearance coming in 2016 when they reached the quarter-finals before elimination to FC Seoul.

A third-place finish in the 2018 Chinese Super League ensured the Jinan side moved within 90 minutes of returning to the competition, while they warmed up for the match by winning the Lunar New Year Cup pre-season tournament in Hong Kong two weeks ago.

The three-time J.League champions finished second in the league last year, having only narrowly avoided relegation a year earlier. But while they have long since been a force in their homeland, they have failed to emulate that on the continent.

Sanfrecce’s best performance in the AFC Champions League came in 2014 when they advanced to the Round of 16 before defeat to eventual champions Western Sydney Wanderers of Australia, while in 2010, 2013 and 2016 they fell at the group stage.

The J.League side were crowned Continental champions for the first time last year but their third-place finish in the league was only enough to grant entry into the 2019 competition’s qualifying rounds.

Kashima, who also reached the semi-finals of the FIFA Club World Cup in December, appeared in the inaugural AFC Champions League and have qualified for the knockout round six times.

Ulsan were crowned champions in 2012 after winning nine games in a row that culminated in a 3-0 victory over Saudi Arabia’s Al Ahli in the final, while they also reached the semi-finals back in 2006.

Last year they were eliminated in the Round of 16 by domestic rivals Suwon Samsung Bluewings, before finishing third in K League 1. They are looking to progress to the competition for the third successive year.

Al Nasr finished third in the 2017-18 UAE Pro League but are sitting below mid-table in the current campaign and lost 1-0 to Al Sharjah on Thursday as their poor run of domestic form continued.

The Dubai side – who have only once reached the knockout rounds (in 2016) – faced Uzbek opposition in the form of Lokomotiv three years ago, with the teams playing out a pair of draws in the group stage. They have never before met Pakhtakor in the competition.

The Islamic Republic of Iran, Qatar and Uzbekistan each have two clubs vying to reach the Continental competition while both Saudi Arabia and the United Arab Emirates have one, with all to be decided in the one-legged match-ups.