Al Nassr struggled in Cristiano Ronaldo's absence on Monday, when the Saudi club kicked off the revamped Asian Champions League with a 1-1 draw against Al Shorta in Iraq.

Al Nassr captain Ronaldo did not travel with the squad for the match in Baghdad, with the club issuing a statement a day before stating that the Portuguese superstar had been diagnosed with a viral infection.

Al Nassr, who were knocked out of last season's Asian Champions League in the quarter-finals by eventual champions Al Ain, were given a dream start in the Iraqi capital, when full-back Sultan Al Ghannam met Otavio's astute, first-time pass on 14 minutes to finish low past Al Shorta goalkeeper Ahmed Basil.

However, the hosts drew level 10 minutes later.

A mix-up at the back between new signings Salem Al Najdi and former RB Leipzig defender Mohamed Simakan allowed Al Shorta forward Mohammed Dawood to steal in and send a superb effort high past Bento in the Al Nassr goal.

Meanwhile, fellow Saudi side Al Ahli eked to a 1-0 victory at home to Iran's Persepolis in Jeddah, with new recruit Ivan Toney making his Asian football debut.

Ivory Coast international Franck Kessie set the home side on their way in the second minute, rifling home from Riyad Mahrez's assist.

Persepolis were awarded a penalty four minutes before half-time, when Merih Demiral was deemed to have committed a foul inside the area, however the decision was overturned following a VAR review.

In the second half, Toney won Al Ahli a spot-kick of their own –- he was felled by rival defender Hossein Kanani -- only for Mahrez's penalty to be saved well by Persepolis goalkeeper Alexis Guendouz.

England international Toney, a high-profile signing late last month from Premier League club Brentford, missed a golden opportunity to open his account five minutes from time, but dragged his shot wide.

He had made his debut for Al Ahli last Friday.

Elsewhere, Al Ain began their title defence with a 1-1 draw at home to Qatar's Al Sadd.

Akram Afif, 2019 Asian Football of the Year and player of the tournament at the Asian Cup earlier this year, opened the scoring at Hazza bin Zayed Stadium on the hour.

But Al Ain earned a point 10 minutes from time, through Argentine Matias Palacios.

In Monday's other match, Iran's Esteghlal saw off Qatari side Al Gharafa 3-0.

The new format features 24 teams -– 12 from West Asia and 12 from East Asia.

With each club playing four matches at home and four away, the top eight in each side of the draw progress to the knockout stages early next year.