Mama is headed back to the U.S. Open finals.
The roof was on at Arthur Ashe Stadium and so was Serena Williams.
After a strategic shift in which Williams turned into a serve-and-volley player, she ran off 12-of-13 games to close out 19th seed Anastasija Sevastova 6-3, 6-0 in Thursday’s semifinals.
Williams, in her first U.S. Open since giving birth last September, moved to her first Open final since 2014 and ninth overall. She’s one win away from tying Margaret Court for the most Grand Slam singles titles at 24.
“Honestly, it is remarkable,’’ the 36-year-old Williams said. “I couldn’t have predicted this at all. This is just the beginning of my return. I’m still on the way up.’’
Imagine if she actually adds a net game permanently?
Williams may have to stay back Saturday when she faces rising-star and 20-year-old Japanese slugger Naomi Osaka, who crushed Madison Keys 6-2, 6-4 in the other semifinal. Osaka is a legit threat after beating Williams in Miami last March.
“This is going to sound really bad, but I was just thinking I really want to just play Serena,’’ the bubbly Osaka said.
Emotion engulfed Williams in the moments after victory as she held back tears, remembering where she was a year ago, suffering blood clot complications from her pregnancy.
On this day a year ago, Williams recalled she had just underwent the third of four surgeries for her second pulmonary embolism — a blood clot that traveled to her lungs.
She’s now in her second straight Grand Slam final after falling short at Wimbledon.
“I got a little emotional out there because last year I was literally fighting for my life in the hospital,’’ Williams said. “To come from that, in the hospital bed, not being able to move and walk and do anything, now only a year later, I’m not training, but I’m actually in these finals, in two in a row. I’m not there yet. I’m on the climb still.”
Williams made her adjustment after falling behind 2-0, broken in the first game and out of rhythm. Sevastova gave her a diet of slices, dropped shots and soft balls.
Williams overhit, then changed tactics. She rushed to the net and overpowered the Latvian in dominant fashion with volley winners and overhead smashes. In her first five Open matches, she came in 26 times total. Thursday, Williams made 28 forays to the net, winning 24 of those points.
“I usually just come in to shake hands, but I knew if I was to beat her I had to come in,’’ Williams said. “I know how to play at the net. I have great volleys, or else I wouldn’t have won so many Grand Slam doubles titles. I know how to do it. It’s just the fact of turning it on and actually doing it.”
After struggling two years ago against dink specialist Roberta Vinci in losing in the Open semifinals, costing herself the Grand Slam, Williams decided she may change.
“This particular player I felt like I needed to come in more,’’ Williams said.
Rain started before the players took the court, prompting the roof to be closed, bringing on perfect conditions after a day of excruciating humidity. The rain stopped, but the roof stayed closed and Williams rolled.
But she cautioned she’s not 100 percent Serena.
“I definitely don’t feel myself yet,’’ Williams said. “I’m definitely not there. I don’t feel like me. I think it takes time. My mom said it takes a full year to get back. I’m at a full year now. I just feel like I’m definitely not there.”
She will find a lot about herself against Osaka, Japan’s first women’s Grand Slam finalist. Osaka was born in Japan but has spent most of her life in the U.S., including Long Island and Florida.
Osaka, who won the prestigious Indian Wells last March, was mentally tough in fighting off 13 break points produced by Keys, the American who made the Open finals last year. Now Osaka has what she craves — a match against Williams — six months after routing her, 6-3, 6-2.
“It was good that I played her because I kind of know how she plays now,’’ Williams said of Osaka. “I mean, I was breast-feeding at the time, so it was a totally different situation. Hopefully I won’t play like that again. I can only go up from that match.”