The first leg of the 2018 AFC Champions League quarter-finals produced two wins for the home sides and as many for visitors. But the competition's history shows the four winners there can be no room for complacency following a first leg victory.

The quarter-finals were introduced in the AFC Champions League back in 2004, and since then we have witnessed some iconic returns after disappointing first leg ties, the-AFC.com recalls three extraordinary comebacks ahead of the second legs.

When Dalian Shide's Hao Haidong was crowned the first top scorer of the AFC Champions League era in 2003, few might have expected it would take six years before anyone could break his record of nine goals in a single tournament.

In 2009, Leandro's Gamba Osaka was the first to do so by getting into double digits, with his tally being surpassed by five other men since.

Whethere it was the goals of Kashima Antlers' Serginho and Han Eui-kwon of Suwon Samsung Bluewings, or the midfield performance by Al Sadd's Gabi and Jung Woo-yung, there were impressive first outings for a number of footballers in Asia as the AFC Champions League re-commenced after the three month break.

When Almoez Ali headed home in the 15th minute, thoughts of Al Duhail’s resounding win over Al Ain in the previous round were not too far away. However, the Iranian giants dug deep to leave the tie firmly in the balance ahead of the second leg in Tehran in two weeks’ time.

Speaking exclusively to the-AFC.com, Xavi expressed his satisfaction with the team's performance at the Azadi Stadium, adding that Al Sadd were much better than their hosts.

"I think we did well but there's one more game," said the 38-year-old World Cup winner. "It could be just 90 minutes or it could even go to extra time. We don't know; in football, we never know.

"At least, we did a really good job in Tehran. It was a very good performance and I think we were much better than Esteghlal, especially in the second half. Also, in the first half, we could have scored at least one goal."

I am happy with our attacking intent. This is the fifth match I scored two goals, but nothing is over yet. We went 50% of the way, but there is another 50% to go in Doha in the return leg.

Baghdad Bounedjah may be the 2018 AFC Champions League's leading scorer, but the Al Sadd striker is intent on avoiding complacency, despite the side holding a 3-1 advantage over Esteghlal after the first leg in Tehran.

In a cagey encounter between the Qatari and Iranian champions at Khalifa International Stadium, chances were at a premium all evening. Al Duhail had to eventually settle for the slender advantage provided by Ali's 15th-minute goal, which saw him head in at the back post following Edmilson's cross from the left.