Boulter missed the 2019 tournament through injury and will now take on Aryna Sabalenka.
The 24-year-old missed the Championships in 2019 with the back problem that plunged her out of the top 100 after a breakthrough season the previous year.
Boulter is ranked down at 219 but she is undoubtedly a better player than that and has shown on many occasions that big stages bring the best out of her.
She had a kind draw against americano qualifier Danielle Lao, making her Wimbledon debut at the age of 30, but had to battle from a set down to win 6-7 (6) 6-3 6-4.
Boulter said: “I worked so hard behind the scenes, which most of you don’t see. So hard every single day. I’ve been through some really tough moments. I found a way through them because I’ve had some amazing people around me.
"Obviamente, having been absent for a couple years, it really means so much. Ultimately it wasn’t pretty out there. I knew it wasn’t going to be. But I fought so hard, found a way. I feel like that’s what tennis is really about.”
It was attack against defence as Boulter, who had her right elbow strapped, unleashed her powerful groundstrokes.
But Lao did a good job keeping the ball in play and, although Boulter fought back from 2-5 e então 4-6 in the tie-break, it was the American who clinched the opening set.
Boulter finally made the breakthrough she was looking for midway through the second set but then trailed 3-1 in the third before winning five of the last six games.
“I think the first set was pretty tough,” said Boulter. “But I was also quite nervous. Before the match I didn’t really have those feelings. As I stepped on to the court, I felt the crowd again, it kind of came back to me a little bit.
“I thought I did a good job to get back into it, having been 5-2 baixa. I’m a little bit disappointed I didn’t get the first set, considering the momentum that I had.
“I’m a fighter. I’m not going to go anywhere. I felt like I loosened up a little bit in the second set and played some good tennis.
“It definitely feels pretty special to be back home. It really does make a difference for sure. I saw some GB flags out there, which made me smile for sure. To have my family out there, it means everything to me. It really helped me get over the line today.”
The victory earned Boulter a shot at second seed Aryna Sabalenka to whom she lost a tight match at the Australian Open in 2019.
“I’m super excited to get out there already,” said Boulter. “I know what to expect. I know she’s a power player. It’s going to be really difficult. She’s ranked what she is for a reason.
“Ultimately all I’m going to do is go out there, enjoy myself, put my game on the line, see what I can do. I’ve got absolutely nothing to lose. I think it’s going to be a really good match.”