The Canadian's breakout season was a stunning success by every metric imaginable. (Getty)

The new year is almost upon us, and there's a crop of young players ready to make even bigger marks on the world in 2020. Let's count down the Top 10 ATP and WTA youth to watch: 

4

Bianca Andreescu

Age: 19 

Ranking: No. 5

From the word Go, almost nothing short of an injury could stop Bianca Andreescu in 2019. 

Starting as an 18-year-old ranked No. 178, who'd never made a tour-level final before, Andreescu won her first seven matches of the year, coming through qualifying to make the final in Auckland. 

Several strong showings later, she took her maiden title, at the BNP Paribas Open, where she defeated top-20 players in each of the last four rounds, including Garbine Muguruza and, in the championship match, Angelique Kerber. 

Having played 35 matches in three months, Andreescu was forced to miss much of the middle of the season due to injury, but on the hard courts, she managed to pick up right where she left off, claiming another prestigious trophy, at the Rogers Cup, in her hometown of Toronto. 

Of course, the rest is history: Andreescu would plow through a stacked US Open draw, besting Serena Williams in straight sets in the final to become a Grand Slam champion at 19. 

Overall, Andreescu went an unbelievable 48-7 in 2019, and finished the year ranked 173 spots higher than she started it—despite going almost five months without finishing a tournament. To the surprise of no one, she was named the WTA's Newcomer of the Year this December. 

All of this begs the question: What would a full season at the tour level look like for Andreescu? Would she be even more dominant? Would the field eventually figure her out? 

One thing's for sure: Don't stop watching just yet.