Russia’s Andrey Rublev needed just eight minutes to reach the Vienna ATP quarter-finals on Thursday when Italian teenage opponent Jannik Sinner was forced to quit.

Fifth-seeded Rublev was ahead 2-1 in the first set when the 19-year-old world number 43 retired with a right foot injury.

Rublev, now in his ninth quarter-final of this truncated season, will face second seed and defending champion Dominic Thiem for a spot in the last-four. US Open winner Thiem eased past Chile’s Cristian Garin 6-3, 6-2.

Bulgaria’s Grigor Dimitrov knocked out third seed and reigning ATP Finals champion Stefanos Tsitsipas 6-7 (5/7), 6-4, 6-3 to record his first top 10 win of the year.

“I was focused, but he went for it,” said world number 20 Dimitrov.

“In the tie-break a few close calls here and there went his way. But I kept on believing and kept on doing the right things.” Dimitrov faces Britain’s Dan Evans for a semi-final place.

Italian lucky loser Lorenzo Sonego defeated Poland’s Hubert Hurkacz 7-6 (8/6), 7-6 (7/2) and next plays world number one Novak Djokovic.

Results

Second round

Lorenzo Sonego (ITA) bt Hubert Hurkacz (POL) 7-6 (8/6), 7-6 (7/2)

Grigor Dimitrov (BUL) bt Stefanos Tsitsipas (GRE x3) 6-7 (5/7), 6-4, 6-3

Dan Evans (GBR) bt Jurij Rodionov (AUT) 7-5, 6-3

Daniil Medvedev (RUS x4) bt Vasek Pospisil (CAN) 4-6, 6-3, 6-2

Andrey Rublev (RUS x5) bt Jannik Sinner (ITA) 2-1 - retired

Dominic Thiem (AUT x2) bt Christian Garín (CHI) 6-3, 6-2