NEW YORK — The world’s most scrutinized right wrist endured its first test at this U.S. Open, and by all accounts, most importantly its owner’s, the joint appears to have passed with flying colors.“It’s pain free right now, I felt great,” Carlos Alcaraz said Monday after beating Roman Safiullin of Russia in straight sets at Arthur Ashe Stadium.Alcaraz won 6-4, 6-4, 6-4 in two hours, 22 minutes, an efficient day at the office for someone coming back from an injury and not wanting to strain himself too much in his first match in four months.“I don’t know how it looked from outside, but, you know, from inside, my feeling was that I was hitting normal,” Alcaraz said. “I was playing pretty normal, playing my style.” He added: “The arm, the wrist, everything felt great.”That was about the best news the tennis world has received in a while. Alcaraz has been out since April and managing tenosynovitis, an injury in which fluid accumulates in the sheath that protects a key tendon in the wrist. Like every tennis player, Alcaraz relies on the wrist of his racket hand to generate the immense levels of speed and spin that make his shots so difficult to handle.It’s the reason tennis players fear a wrist injury more than any other. Knee, elbow and shoulder injuries can be managed. A wrist injury can doom a career.Alcaraz’s injury has kept him out of two Grand Slams this year. He pulled out of the French Open a month before it started and withdrew from Wimbledon nearly six weeks out, signaling his team’s cautious approach to the injury and also its seriousness.He targeted Cincinnati in mid-August as his comeback event. But he pulled out of that about a week before its start.Then came a message on social media nearly two weeks ago: “Here we go.” He teamed with Serena Williams in mixed doubles last week, winning one match and losing the second in what figured to be a sensible test and warmup for the wrist.Carlos Alcaraz working on wrist mobility exercises with physical therapist Juanjo Moreno during a practice session Sunday. (Clive Brunskill / Getty Images)A best-of-five set singles match, however, is a test of a different magnitude. So there was plenty riding on the first round.