Alexander Zverev celebrated his comeback 188 days after his serious ankle injury.
At the quite controversial show event in Diriyah/Saudi Arabia, the Olympic champion defeated his Austrian buddy Dominic Thiem 10:8, 10:7 in a match tiebreak format.
The German top player had not played a match since suffering a serious ankle injury on June 3 in the semi-finals of the French Open.
"To be honest, I was just happy to be back on the pitch and largely pain-free," said Zverev after the match: "It's not an ATP tournament or a Grand Slam, but it's a nice feeling to be back in one competition to be part of.”
Against Thiem, whom he narrowly lost in the 2020 US Open final, Zverev played with his foot taped but moved well.
In his own service in particular, he radiated the dominance that had taken him to second place in the world rankings.
He continues in the quarterfinals against the Russian Daniil Medvedev.
The match will be played on Thursday.
Zverev canceled his first comeback attempt in September shortly before the Davis Cup group phase in his hometown of Hamburg.
Bone edema forced the 25-year-old to end the season early, dropping out of the top ten for the first time in five years.
Five of the currently ten best players are at the start of the financially lucrative tournament in Saudi Arabia.
Human rights organizations repeatedly criticize that fundamental rights are not observed in the country.