Maria Sharapova reflected positively on her US Open campaign after the former world number one's grand slam comeback ended in the fourth round.

Sharapova bowed out at Flushing Meadows on Sunday following a 5-7 6-4 6-2 loss to 16th seed Anastasija Sevastova in New York.

The five-time grand slam champion was making her first major appearance since the 2016 Australian Open, having tested positive for a banned substance at Melbourne Park last year.

Sharapova returned from a 15-month suspension in April after violating anti-doping rules, but was denied a wildcard for the French Open and then pulled out of Wimbledon qualifying through injury.

The 30-year-old Russian upstaged Simona Halep en route to the round of 16 but she fell to Sevastova, though the 2006 US Open champion was not too downcast post-match.

"It's been a really great ride in the last week," Sharapova told reporters. "Obviously coming off a loss, you know, it's a quick turnaround in order to reflect all the positives that happened in the last eight or nine days.

"But ultimately I can take a lot from this week. It's great to get that major out of the way. It was an incredible opportunity. I'm very thankful for the opportunity. I did my best. I can be proud of that."

She continued: "I think there are a lot of positives. Playing four matches, playing in front of a big crowd and fans. Just competing, being in that competitive environment. That's what I missed.

"You can't replicate that anywhere, especially at a grand slam. So for me to come out, Monday night was a special night for me. I will always remember it. I'm very grateful to have had that opportunity to bring it.

"As I said, I came in not playing a lot of matches. We all know that. Didn't have much practice.

"Obviously always disappointing to be on the losing end of things. But, yeah, I mean, reflecting back on the week, I can be happy."

Sharapova had previously said she would retire by the age of 30 when asked if she would play on until 2018 during her Australian Open campaign nine years ago.

"I hope by that time I'll have a nice husband and a few kids," Sharapova said in 2008.

Fast forward to 2017 and Sharapova has no plans to walk away from tennis.

"I was in my middle 20s, I didn't think that my body would be ready to compete at such a level," Sharapova said as she re-visited the topic. "And I just got a completely new appreciation of what the body can do at 30 years old, or past 30 years old.

"I mean, I can take a lot of examples from champions that are still playing, competing, and doing incredibly well, and that's inspiring. But also personally, what I'm able to do with my body, when I'm training, when I'm competing. Just never really thought that I'd have that capacity. I think that's given me confidence."