MELBOURNE, Australia (AP) -- Madison Keys turns 20 next month and her mother, Christine, is already sending her teasing texts featuring grandma emojis.

''I'm like, `Thanks for reminding me, Mom,''' she said. ''Thank you. Love you.''

It's a good thing for Keys she's making the most of her last Grand Slam as a teenager, beating fellow American Madison Brengle 6-2, 6-4 in the battle of the Madisons at the Australian Open on Monday to reach the quarterfinals of a major for the first time.

She may have been the younger player on the court - Brengle is five years older and was also playing for her first major quarterfinal - but Keys has looked increasingly comfortable as she's progressed deeper into the draw with her new coach, Lindsay Davenport, watching from the stands.

Then again, she has faced expectations as the next American tennis hope since she played - and won - her debut match on the WTA Tour in 2009 at the age of 14, the youngest player to do so since Martina Hingis.

The pressure has only increased with Serena and Venus Williams getting older and other young Americans such as Melanie Oudin and Sloane Stephens struggling to build on early successes and close the gap between the generations.

''It's definitely been an experience, really playing well, kind of living up to what people have been saying,'' Keys said. ''I'm just really happy that it's finally here and that I'm doing so well.''

If her run is going to continue at Melbourne Park, she's next going to have to beat one of the Williams sisters - and perhaps both. Her next opponent is the 34-year-old Venus, who couldn't help joking about the age difference between herself and Keys.

''She started watching me when she was in diapers,'' Venus said, laughing.

If Keys beats Venus, she could then face 18-time major winner Serena Williams in the semifinals.

Serena wouldn't be surprised to see her there, either. In fact, Keys is playing so well, Serena Williams said, she could carry the U.S. team when they travel to Argentina together for the Fed Cup.

''If she continues to play really well, I'm going to offer her to play my matches so I can have a little bit of a break,'' Serena said. ''She just has so much unbelievable potential and she's so young.''

She is still only 19, but Keys doesn't sound content with just reaching the quarters in Melbourne. She said Davenport, a three-time major winner, has given her the belief she can beat any player.

And if anyone can give her the right strategy for her next match, it's Davenport, who played Venus Williams 27 times in her career, winning 14 of those encounters.

''I think it's a huge opportunity for me. I haven't been in this situation before, I'm going to make the most of it,'' Keys said. ''But at the same time, not matter what, I'm not really going to be satisfied with any win. I want to be at the end of the tournament holding the trophy up.''