Dominic Thiem ended a lengthy wait to reach an outdoor hardcourt semi-final by defeating Stefanos Tsitsipas 7-5 6-4 at the Qatar Open.
World number five Thiem reached the last four at five different tournaments in 2017, but each of those came on the clay courts.
But he has managed the feat for the first time since February 2016 at this maiden tournament of the season, while the last hardcourt semi he played in was the indoor Moselle Open in September of the same year.
Thiem was flawless throughout, hitting 33 winners, making 10 successful shots out of 12 at the net and winning 60 per cent of second-serve return points.
"I was serving well again and returning well. That's what I was working on in the off-season so it already pays off now," Thiem said of his win.
Standing in Thiem's way of reaching the final is Frenchman Gael Monfils, who was a 6-3 7-6 (8-6) victor over Peter Gojowczyk.
In a rematch from November's NextGen semi-finals, Andrey Rublev again had the measure of Borna Coric, with the Russian coasting to a 6-3 7-5 victory.
Fellow unseeded player Guido Pella awaits Rublev in the final four, with the Argentinian comfortably defeating Mirza Basic 6-2 6-3.
