EXCLUSIVEYasiel Puig tells TMZ Sports ... he was PUMPED to get Mo'ne Davis to sign his baseball ... and says it's already on display at his house -- right next to a Kobe Bryant autographed basketball.
"She's the best pitcher I've ever seen at her age," the L.A. Dodgers star says ... adding that he couldn't wait to meet the 13-year-old Little League phenom when she threw out the first pitch at Dodgers Stadium earlier this week.
"I think [throwing out the first pitch] was a great moment for her. I was very happy for her."
Puig also says he's rooting for Davis to become the first female pitcher in MLB one day -- saying, "Nothing is impossible when you have talent and will. I wish it would happen for her."