After going up a set despite committing 21 unforced errors, de Minaur reeled off the opening 14 points and 17 of the first 18 in the second set – including two breaks – to transform a once-competitive contest into a rout.
Moutet even mockingly raised his arms in triumph after a de Minaur forehand cleared the baseline to deliver him his first service point of the set in the fifth game, but briefly managed to make things interesting again.
The Aussie double-faulted on break point as Moutet pulled his 4-0 lead back to 4-2, then dropped serve again when de Minaur tried to serve out the match two games later, but a fourth break for the set terminated the Frenchman’s comeback hopes.
De Minaur last reached the Washington final seven years ago, losing in straight sets to Germany’s Alexander Zverev.
This time, he awaits the winner between rocket-serving American star Ben Shelton and his childhood Spanish rival Alejandro Davidovich Fokina.
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Moutet – full-time tour pest and occasional rapper who courts constant controversy, including being booted out of his own country’s federation for bad behaviour and being booed by fans in Madrid this year – became increasingly frustrated as the match slipped away.
The diminutive left-hander copped a code violation at the end of the first set for snapping his racquet over his right leg, after angrily bouncing it into the court in reaction to going a set down.
It was the end of a remarkable run from Moutet, who lost in final-round qualifying but received a second chance at the title as a lucky loser when Holger Rune withdrew. He will make his top-50 debut next week as a result.
But the stakes are far higher for de Minaur, who is currently one spot out of the automatic qualifying places for the end-of-year tour finals.
The 26-year-old has the chance to challenge his career-high ranking of No.6 if he can produce a strong finish to the season, given he missed significant time at the end of last year recovering from a torn muscle high on his hip and has relatively few points to defend.
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