Crespo will be hoping for a different outcome from the last time he faced Kewell, who was part of the Liverpool side that fought back from 3-0 down in Istanbul to defeat AC Milan on penalties and win Europe's premier club competition in 2005.
"It's amazing the situation, we will face him in another Champions League final," said former Argentina star Crespo, who has been in charge of the UAE's Al-Ain since November.
"I always face him in great events. It was a very difficult night for me (in 2005), but it's like this.
"We face each other again and it's a pleasure to meet him again after a long time.
"Life keeps going and we try to reinvent our lives - and we are here again to be competitive like when we were young."
The teams meet in the first leg of the decider at Yokohama International Stadium in Japan, with both having overcome the odds to reach the final.
Al-Ain are appearing in their fourth Asian Champions League final, having lost in 2005 and 2016. They lifted their only continental crown in 2003.
Crespo's side defeated heavily favoured Saudi Arabian clubs Al-Nassr and Al-Hilal in the quarter-finals and semi-finals respectively and will meet a Marinos side attempting to win the title for the first time.
Kewell's team laboured throughout the knockout rounds, needing extra-time to beat Bangkok United in the last 16 before getting the better of China's Shandong Taishan in the quarter-finals.
They beat South Korea's Ulsan Hyundai on penalties to reach the final.
"We've given ourselves a wonderful opportunity to do something special for this club," Kewell said after his 10 men clung on to beat Ulsan.
"From the moment I've come here everyone's really worked hard to achieve something special.
"They believe now they can handle any kind of pressure."
Al-Ain will host the second leg on May 25.
"It's not easy to reach the final in Asia now," said Crespo.
"You play in a final, a high event, and it's special. It's a very beautiful experience to be part of."
- with AAP
