Jelenafan
Multiple Major Winner
Good stats, IIRC wasn't Aaron K the youngest ATP top 10 ever in the Open era?Andy first reached the top 10 on April 16 of 2007, about a month before he turned 20. So there was a month. (He wasn't consistently in the top 10 until July of 2008). So May 14, 2007 would be the answer to your question, I think. Novak was #6, Murray #10.
Agassi and Chang were both in the top 10 as teenagers for at least part of 1989-90, before Agassi turned 20 in April of 1990. Sampras reached the top 10 in August of 1990 at 19, when Chang was still 18. Ivanisevic was also in the top 10 as a teenager for parts of 1990. So there was a cluster back in the 1989-90 range, of Agassi, Chang, Sampras, Ivanisevic. Not sure if anyone else.
I know Edberg and Becker were both in the top 10 in 1985 as teenagers.
Here's a weird one I find: for a brief time in 1984, Mats Wilander and Aaron Krickstein were both teenagers in the top 10. Wilander turned 20, but Krickstein first reached the top 10 right after turning 17 years old.
What’s ironic is he’s most remembered by some tennis fans as being one of the victims of one of the oldest Players ( Connors) reaching his USO SF circa 1991.