Lendl, who was named as Murray's coach at the turn of the year, was in his corner at the Australian Open on Monday as the world number four eased into the last eight after Kazakhstan's Mikhail Kukushkin was forced to retire after losing the opening two sets due to a hip flexor problem.
Murray's 6-1 6-1 1-0 victory in just 49 minutes gave him his seventh quarter-final appearance in his last nine grand slam events, and Lendl believes the experience he has gathered on the way will stand him in good stead.
He said: "Part of it is maturing, he is still a fairly young player, he is 25 this year.
"He needs experience and some players learn quicker than others, I was one of the slower ones.
"You just do your thing and keep on doing it and when the door opens you have to step through it."
Murray has reached three grand slam finals but has yet to win one - failing even to take a set - while Lendl lost his first four before going on to land eight major crowns.
And the 51-year-old points to the quality of the opposition the Scot has faced as another reason not to panic.
He added: "Everyone makes a big thing of Andy being 0-3 in finals but he lost twice to Roger (Federer), arguably the best player of all time and certainly in the Open era.
"Losing to Novak (Djokovic) here last year at the time looked like a bad loss but if that had happened at the US Open everyone would have said Novak had had a fantastic year and no-one would have been riding Andy's tail."
Next up for Murray is a meeting with young Japanese star Kei Nishikori, who stunned sixth seed Jo-Wilfried Tsonga in five sets.
And Lendl was refusing to look beyond that.
"It's one match at a time, no player gets to the quarters without being a very good player," he said on ESPN.
"Nishikori is a young player, he played a very good match today [Monday] and this is the next goal."