The game ended goalless but could have gone either way with both sides creating enough chances to claim all three points.
After a slow first half, Messi began to express himself after the break, but veteran goalkeeper Mohamed El Shenawy was equal to the task.
Reflecting on his side's performance, the new head coach of the Egyptian Premier League champions admitted he was expecting to beat the Major Soccer League side.
Riveiro told DAZN after the match: "It's a football game; it's a game of mistakes. I think we had a decent amount of chances in the first half to put the game in a different space.
"Second half, we were defending a bit lower than what we wanted, and then we had some problems in the transitions as well."
Al Ahly are next in action against Palmeiras on Thursday.
The Spaniard added: "Now we need to recover. It's difficult to speak about Palmeiras. We prepare for the game as well as we can. We are going to analyse what happened today in order to try and avoid the same mistakes."
Borussia Dortmund head coach Niko Kovac has acknowledged the challenge that awaits his side when they face South African champions Mamelodi Sundowns in their upcoming FIFA Club World Cup Group F fixture at TQL Stadium in Cincinnati on Saturday.
Al Ahly striker Trezeguet promises to fight to win their final Group A clash against Porto despite a 2-0 loss to Palmeiras at MetLife Stadium on Thursday.
Jose Riveiro was disappointed to lose his first game in charge of Al Ahly in the Club World Cup Group F encounter with Palmeiras on Thursday.
Divine Lunga admits it is a strange feeling heading into their Club World Cup clash against German giants Borussia Dortmund as underdogs.
