Baseline is looking ahead to the new year by showcasing 21 players under 21 to watch out for in '21. To make the coveted list, players must be born in 2000 or later. 

San Diego native Brandon Nakashima made his mark immediately upon entering the ATP level this year, taking advantage of a Delray Beach wild card by recording wins over Jiri Vesely and Cameron Norrie. He backed that result up at the US Open, where he defeated Paolo Lorenzi before taking a set off Alexander Zverev in the second round. 

Additionally, he won both an ITF and a Challenger title, showing that he's already ready to compete at all levels. All of this makes him one of men's tennis' highest-ranked and most promising teenagers. 

Ranking: No. 166

Age: 19 (Aug. 3, 2001)

What he did in 2020: Won Rancho Santa Fe ITF and Orlando Challenger titles, victorious in his first main-draw US Open match 

Instagram: @brandon_nakashima

Career highlights​: Having made his tour-level debut this year, Nakashima doesn't have too much history to look back on. However, in addition to the successes already mentioned, he took the title at the 2018 ITF event in Laguna Niguel, Calif.