The Reds hero marked his 600th game for the Merseyside club on Sunday, helping Brendan Rodgers' side to a 1-1 draw with Newcastle at Anfield.
And Alonso, who played alongside the Huyton-born midfielder for a five-year period between 2004 and 2009, believes that Gerrard has the quality to match the likes of Andres Iniesta, Xavi and himself.
"Absolutely, there's no doubt," he told Real Madrid TV. "He could play in any national team in the world because he has so many great qualities.
"He is flexible. He can play at the English pace or he can associate with the ball very well. He is a very intelligent player, so he could play anywhere - not just any national team but any club in the world. But he has been a one-club man and that's something I really admire."
The 30-year-old also revealed how influential Gerrard has been on his own career, explaining that the way he conducted himself both on and off the pitch left a lasting impression.
"We are great friends and we still keep in touch. He was a great influence to me," Alonso continued.
"When I arrived at Liverpool I was 22 and he was the captain, he was the main man at the club.
"For me he was a reference, the way he behaved with his teammates and with the supporters as well. I learned a lot from him.
"As a captain he has embraced all the responsibilities of being a captain and he's the perfect captain for Liverpool, not just because he's a great player but because he represents the values of the club."
Alonso went on to insist that Gerrard's failure to clinch a league title with Liverpool will not detract from his status as a legend in the game, declaring: "He'll absolutely be remembered as one of the greats. For me he is already one of the greats.
"His name and Liverpool's name will always be linked and he's a great representative of the club and the city.
"There are so many things. He is so inspirational. In the key moments he has that different thing, that spark that is difficult to define.
"He has achieved great things and in very important moments he has been the man for Liverpool. We had great European nights and he was the main man. For me he's a great player. Hopefully he will reach 700 games."