Teenage tennis sensation João Fonseca frustrated his home fans at the Rio Open in a first-round loss Tuesday, two days after winning his first ATP title. Fonseca lost 6-1, 7-6 (4) to No. 60-ranked Alexandre Muller of France, making 34 unforced errors and appearing to be exhausted during the match. Muller will meet Argentina's Tomás Martin Etcheverry in the next round.