Over the past year, the Scot had won both the Wimbledon and US Open Grand Slams, finished runner-up at the Australian Open as well as earning an Olympic gold medal, yet still sits behind Novak Djokovic in the world rankings.
The Serbian is placed above the British number one due to his consistency in the second tier of tennis events known as the Masters series, but Lendl feels that Murray is worthy of taking his place at the top.
"Under pressure right now Andy has two majors and a gold medal," Lendl told The Telegraph.
"Novak is a great player, don't get me wrong. He has had a phenomenal last 12 months, basically since the start of 2011, so the rankings look at all of that.
"[But] if somebody has two majors and an Olympic gold medal, and everybody else has only one major, everybody can make their own opinion on that."
Lendl has coached Murray since the start of 2012.