In the 2009 French Open, he entered the Boys' Singles as an unseeded player. He defeated 9 seed Facundo Argüello in the first round. He then won against Pablo Carreño Busta and Federico Gaio to reach the quarter-finals, where he defeated Richard Becker in straight sets. In the semi-finals, he defeated Henri Laaksonen to reach his first ever junior Grand Slam final. He defeated French player and 11 seed Gianni Mina 6–1, 3–6, 6–3[1] for his first ever junior Grand Slam title[citation needed].
In the junior 2009 Wimbledon Championships, Berta lost in the third round to American Alexander Domijan 3–6, 3–6.
He was granted a wildcard into the 2009 Ordina Open, which was his ATP tournament debut. He lost to Belgian qualifier Dick Norman in the first round, 3–6, 3–6.
[2][3] He also received a wildcard into the 2009 Swedish Open, where he lost to Björn Phau in the first round 3–6, 2–6.