“We made a lot of mistakes, and it cost us the match. It's very difficult for us to accept this result,” said Pioli. 

“We approached the game with a different strategy but we made too many errors in the first half. Now, it's time to shift our focus back to the Saudi Pro League.”

Despite getting off to a fast start, Al Nassr found themselves chasing the game after Tatsuya Ito put Frontale ahead in the 10th minute. 

Sadio Mane equalised in the 28th minute but Frontale edged ahead again four minutes before the break through Yuto Ozeki, with the goal coming after Cristiano Ronaldo had rocked the crossbar with a header in the 33rd minute. 

Akihiro Ienaga further widened the lead against the run of play in the 76th minute, with Aiman Yahya’s 87th minute strike giving Al Nassr hope. Ronaldo had three attempts on target as the seconds ticked away, with Frontale holding on for the win. 

“We didn’t perform the way we should have but from the start, we were determined to give our best. We'll continue to fight and work hard to improve. 

“I share the fans' disappointment and take full responsibility. Sometimes, the circumstances of a match are beyond your control but we still need to do better.”

The Italian tactician admitted Al Nassr were caught off guard by Frontale’s intensity and tactical execution.

“Kawasaki surprised us with their level. Our biggest issue was a lack of discipline and too many mistakes, we didn’t play to our potential.

“Tactics evolve from match to match but today we simply didn’t meet our standard. We understand the criticism. We knew the opponents’ style but we just weren’t good enough.”