Saudi Arabia's Al-Hilal handed defending champions Al-Ain a dramatic 5-4 defeat in the Asian Football Confederation (AFC) Champions League Elite on Monday as Salem Al-Dawsari's hat-trick in an incident-filled clash overshadowed Neymar's return to competitive action.

Neymar, who has been sidelined since a cruciate ligament rupture last October, was a 77th minute substitute as the Saudi Pro League side avenged last season's semi-final loss against Al-Ain despite playing the closing stages with 10 men.

The win keeps Al-Hilal on top of the league standings in west Asia after three rounds with nine points, where they are joined by fellow Saudi side Al-Ahli after their 2-1 win over Qatar's Al-Rayyan.

Gabri Veiga scored direct from a corner to give Al-Ahli a 16th minute lead before Feras Al-Brikan headed in his side's second seven minutes from the break, although Fahad Al-Hamad's own goal left his side clinging on for the final 25 minutes.

Qatar's Al-Sadd picked up their second win of the campaign to move onto seven points as Matheus Uribe's first half goal downed Persepolis of Iran while Al-Shorta from Iraq and Pakhtakor of Uzbekistan played out a 0-0 draw.

Al-Hilal's third consecutive win in the competition came as Jorge Jesus' side edged their hosts in a nine-goal thriller at Hazza bin Zayed Stadium in which both Al-Dawsari and Al-Ain's Soufiane Rahimi scored hat-tricks.

"There were a lot of goals, a lot of chances and we managed to win the game with one player less in the end, so it's a big win for us," said Al-Hilal striker Aleksandar Mitrovic.

Al-Hilal had taken the lead in the 26th minute through Renan Lodi's low strike but Rahimi levelled from close range with six minutes left in the first half.

However, an injury-time header from Sergej Milinkovic-Savic was quickly followed by a strike from an acute angle by Al-Dawsari that gave the visitors a two-goal cushion going into the interval.

Substitute Mateo Sanabria pulled one back for Al-Ain 18 minutes after the restart only for Al-Dawsari to score again barely 90 seconds later.

Rahimi hit his second in the 67th minute but Al-Dawsari's strike looked to have put the result beyond doubt with 15 minutes left, allowing Jorge Jesus to introduce Neymar for the first time since rupturing his cruciate ligament last year.

However, Ali Al-Bulahyi's red card for hand ball just outside the area piled the pressure on Al-Hilal and Rahimi completed his hat-trick from the penalty spot six minutes into added time after he was upended by Khalifah Al-Dawsari.

The result keeps Al-Hilal perfect after three rounds while Al-Ain have yet to win in the revamped competition, which sees the top eight finishers in the league phase in both east and west Asia advance to the knockout rounds.