Daniil Medvedev stayed on course to win back-to-back tour titles and denied Jo-Wilfried Tsonga the same opportunity with a straight-sets win at the ABN AMRO World Tennis Tournament in Rotterdam.
Medvedev, who claimed the Sofia Open title last week, extended his winning streak to seven games with a 6-4 6-2 win over the Frenchman, who had also triumphed at the South of France Open.
The fifth-seeded Medvedev was in no mood to see his run come to an end, breaking Tsonga in the opening game of the match and retaining the advantage throughout.
Two more breaks in the second set secured victory for the Russian, who admitted to atptour.com: "It feels a little strange as I don't think I played that well, but I managed to work hard."
In the last four Medvedev will face French veteran Gael Monfils - whom he also overcame at the same stage in Sofia.
Monfils needed just 69 minutes to dispose of Bosnia's Damir Dzumhur 6-1 6-2, breaking his opponent five times as he secured a comfortable victory.
The other semi-final will see number one seed Kei Nishikori face Stan Wawrinka.
At the New York Open, number one seed John Isner beat seventh seed Jordan Thompson of Australia in straight sets 6-4 6-1, while last year's runner up Sam Querrey needed three sets to see off Jason Jung 6-3 3-6 6-3.
The third American in the semi-finals is Reilly Opelka after a 6-3 6-4 win over Guillermo Garcia-Lopez, while Canadian Brayden Schnur edged out Paolo Lorenzi 6-7 (7) 7-6 (5) 7-5.
In Buenos Aires, Dominic Thiem will face Diego Schwartzman in the semi-finals after the Austrian beat Pablo Cuevas 4-6 6-4 6-3 and the Argentinian saw off Albert Ramos 6-1 7-5.
Guido Pella and Jaume Munar exchanged five breaks in a lengthy second set tiebreak, with the Argentine taking the set and the match 6-7 (3) 7-6 (9) 6-1. World number 18 Marco Cecchinato beat Roberto Carballes Baena 7-6 (3) 6-4.
