NEW YORK — Even before Serena Williams set foot in Arthur Ashe Stadium on Monday night, her path through the U.S. Open to complete a true Grand Slam became a lot easier thanks to losses by other top women.

And when it was the No. 1-seeded American’s turn to play her first-round match, she was not tested one bit by a woman who appeared overwhelmed by the opponent, the occasion and, to make matters worse, an injured left foot.

So Williams moved a step closer to tennis’ first calendar-year Grand Slam since 1988 without much of a workout, reaching the second round when 86th-ranked Vitalia Diatchenko of Russia stopped playing while behind 6-0, 2-0. Williams was out there for only 27 minutes and took 32 of the 37 points that were played.

“It was definitely different and bizarre,” Williams said. “But at the same time, I was still focused. I kept thinking: Just stay focused; don’t lose it. You never know what can happen.”

The 33-year-old American told the crowd she appreciates the support she is receiving “on this journey and this milestone that I’m trying to take one match at a time.”