Alexander Zverev says he hired Ivan Lendl to help him compete meaningfully in grand slams, as the rising German star targets an improved performance at the US Open.

Zverev is among the most promising young players on the ATP Tour, having won 14 events, including three Masters 1000 tournaments, to reach fourth in the world rankings.

However, the 21-year-old has only advanced to the quarter-final of a slam once, and has not progressed beyond the second round of the US Open.

Zverev began working with Lendl, who coached Andy Murray to all of the Brit's three slams, ahead of the final major of the year at Flushing Meadows. 

And the motivation behind the addition of the Czech to Zverev's team is no secret.  

"The reason I'm with him is to compete and win the biggest tournaments in the world," he was quoted as saying by the ATP website. 

"That's the only reason he would join, as well. It's great having him here. Hopefully it will show in the results.

"He's a smart man, a great guy. Done it as a player, done it as a coach, so he knows what it takes. He knows how to do it. He knows how to make the best players even better. This is why I took him.

"There's a lot of tactical work [to do], for sure. There's a lot of mental work, as well, to kind of show me what it takes to compete for grand slams, to win grand slams.

"That for sure he has shown me a little bit.

"I'm trying to play my best tennis here in New York, which I've never really done before. I've never really played the best tennis here … I'm trying to change it this year. Hopefully it will work out that way."

Asked how long he expects the relationship to last, Zverev replied: "As long as it works. If I win the US Open here, it's going to be probably a little while."