Umag - Rogerio Dutra Silva upset second-seeded Gael Monfils 7-6 (5), 4-6, 6-3 to reach the quarterfinals of the Croatia Open on Thursday.
The 64th-ranked Brazilian next faces Italian Alessandro Giannessi, after he beat qualifier Kenny De Schepper of France 6-2, 3-6, 6-3.
Also in the second round, defending champion Fabio Fognini overcame a second-set wobble to win 6-4, 1-6, 6-2 against unseeded Nicolas Kicker of Argentina.
The third-seeded Italian had his serve broken twice set by Kicker in the second set.
In the quarter-finals, Fognini will play lucky loser entry Andrey Rublev of Russia.
Rublev beat last year's finalist Andrej Martin of Slovakia 7-6 (5), 7-5.