Messi scored a second-half brace to guide Barca to a 3-0 win over Liverpool in the first leg of their Champions League semi-final at Camp Nou on Wednesday.
The Premier League side squandered numerous chances and seemed to have Messi under control before the star forward doubled his side's lead and then curled in a wonderful 30-yard free-kick.
Robertson felt Liverpool defended Messi well and he hopes they can keep the 31-year-old quiet in the second leg at Anfield on Tuesday.
"We know how good he is. We're not going to hide away from it. He's the best player in the world, but I thought we done relatively well against him," he said.
"He scored a tap-in and then, look, the free-kick is world class and you can't get in the way of that, but how many times has he done that?
"Look, a world-class player but hopefully can we keep him quiet on Tuesday and let's see what we can do."
Liverpool managed to keep Messi quiet until the Barca captain pounced on a rebound after Luis Suarez – the scorer of the opening goal – had hit the crossbar.
Virgil van Dijk said Messi made life difficult for the Reds and had proven he could deliver when needed.
"He's a fantastic player, that's pretty obvious. I think the difficult part against him is when we are attacking he's chilling somewhere in the corner or something. So you need to be so aware with the defensive organisation," the centre-back said.
"We knew how it would be, we knew we could overplay on that side, but when we lose easy balls or difficult balls they just try to find him and make it difficult for us on the break.
"I think he's the best player in the world and he's got that little bit extra as well that he's shown over the years."