ROLAND GARROS, PARIS — Coco Gauff is heading back to the French Open final.She booked her spot in a No. 2 vs. No. 1 showdown against Aryna Sablenka with a commanding win over Loïs Boisson, the French wild card who had become the toast of the tournament. Gauff, who so often has crowds behind her, entered enemy territory Thursday evening, taking on Boisson and 15,000 French fans ready to blow the roof off Court Philippe-Chatrier.She beat both, badly. Gauff matched Boisson shot for shot in nearly every rally, either waiting for the error or a ball she could jump on. When it was over after 70 minutes, she had a 6-1, 6-2 triumph over a woman who had spent the past fortnight scrambling the brains of some of the best players in the world.After looking like a superstar for 10 days, Boisson, with Gauff’s help, reverted to a player who only this week broke into the top 100.There are a couple of different ways Gauff loses matches these days. Sometimes she loses control of her serve and her groundstrokes and can’t find the court. Other times, a power-player like Sabalenka plays first-strike tennis against her, taking time away.Like most players, Gauff craves time to set her feet and get her body behind the ball. She’s as good as anyone at using her legs to steal time back, covering the court like no one else, getting enough balls back on the run that she can take back control of any point, however lost.It’s been a while since someone beat Gauff at her own game in a big tournament, but that’s what Boisson tried to do at the start of the match. It was hard to blame her, since that approach had carried her from being an unknown wild card to a semifinal berth.She had lulled one opponent after another, including two of the WTA top six, into a maze of deep, looping topspin forehands, tricky low slices and then sudden, surprise-attack power. Add in Boisson’s serious speed and fitness and it can be a very dangerous approach, especially on the red clay of Europe that rewards those who can play attritional tennis if they also possess some kill shots.In Gauff, Boisson was facing one of the masters of that game, a six-year veteran of Grand Slam tennis with an engine honed in the heat of south Florida, who can run all night on a cold spring night in Paris. Boisson is good at that game. Gauff is just better at it. At least she was Thursday evening.“She played on the right and on the left and on the right” a slightly dazed Boisson said in her news conference.“I just feel like I was running everywhere on the court today … I couldn’t play my game today because she was just too good.”