The Scot has enjoyed a landmark 2012, winning his first major championship at the US Open alongside an Olympic gold medal.
Lendl thinks that Murray can go on to win more Grand Slam titles in 2013 if he maintains the consistent standard of tennis produced this season.
He told the Evening Standard: "Nothing is God-given, it's all about hard work. Andy has worked really hard to have good hands around the net and to hit the shots he does.
"I don't see why Andy should not have another big year in 2013. I've never been a fan of how many weeks someone is at number one. I'm more interested in winning majors because then No1 comes as a byproduct and it shows consistency.
"It's a good call by Andy to aim to become number one in the world and he understands that it's not only about playing well in the majors, it also takes consistency throughout the year to achieve that. I don't see any reason why Andy won't win many more Grand Slam titles."