Doha, Feb 23 (IANS): Jiri Lehecka earned the biggest win of his career by ATP Ranking on Thursday at the Qatar Open, where he upset World No. 5 Andrey Rublev 4-6, 6-4, 6-3 to reach his second tour-level semifinal, here.

The 21-year-old Czech entered the clash off the back of straight-set wins against Damir Dzumhur and Emil Ruusuvuori and he demonstrated his confidence levels in a heavy-hitting performance against the top seed.

Lehecka timed the ball cleanly off both wings, causing damage with his flat forehand to hit through a frustrated Rublev. He broke twice, sealing his victory after one hour and 41 minutes to improve to 1-1 in his ATP head-to-head series against Rublev.

"These past two months have been very great for me. I was very much looking forward to playing here in Doha on this beautiful centre court, so I am very happy with the win and looking forward to tomorrow," Lehecka said in his on-court interview.

The Czech will aim to advance to his first tour-level final when he faces former World No. 1 Andy Murray or French qualifier Alexandre Muller on Friday. Lehecka, who is up eight spots to No. 44 in the ATP Live Rankings, reached the semi-finals in Rotterdam last year.

Lehecka ended his 2022 season in style when he reached the Next Gen ATP Finals title match in Milan. Using that run as a springboard, he has made a fast start to 2023. The 21-year-old now holds an 11-3 record on the year, highlighted by his quarter-final run at the Australian Open, where he earned his first Top 10 win against Felix Auger-Aliassime.

"I have improved everything. Mostly my mentality on the court. I gained confidence from NextGen and now I have learnt how to use it," Lehecka said while reflecting on his progress.

Rublev was aiming to continue his impressive record at the ATP 250 hard-court event, having reached the final in 2018 and won the title in 2020.