The 30-year-old Real Madrid midfielder played alongside Gerrard for four seasons before moving back to La Liga to join Los Blancos in 2009.
The pair were the backbone of the Liverpool side which won the Champions League and FA Cup in successive seasons in 2005 and 2006, and Alonso praised the England skipper for his loyalty to the Reds.
“Absolutely, there’s no doubt,” Alonso said when asked if Gerrard is good enough to play for Spain.
“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.”
Alonso, who has been linked with a return to the Premier League, revealed how Gerrard helped the former Real Sociedad midfielder develop as a player during his time at Anfield.
“We are great friends and we still keep in touch,” he added.
“He was a great influence to me. 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.”
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