The 25-year-old Scot was bed-bound for several months after an initially mild bout of coronavirus in October 2020 turned into something much more debilitating.
She feared her career could be over but was finally able to make a tentative return to the court last spring and happily that turned into a full-time comeback.
Earlier this week, she was rewarded for an excellent season in doubles, including a run to the quarter-finals of Wimbledon, with a first call-up for Great Britain for this weekend’s play-off against Sweden in London.
“During that period, I didn’t think I would get back to playing for a while so to now be in the GB team’s obviously unbelievable,” Lumsden told the PA news agency.
“I feel like it hasn’t really fully sunk in, the last four weeks I’ve played four tournaments in a row, so I feel like it’s come around pretty quick.
“It’s a huge moment for me. It’s an amazing feeling to get selected for GB for the first time and get to be in this team with all the other girls is really cool. A lot of them are really experienced and have played a lot of ties so it’s great to be around everyone.
“The first time I saw professional tennis was the Davis Cup ties at Braehead (in Glasgow) so I’ve always loved team competitions and it’s been a goal to get in a team like this because that was what inspired me when I was younger.”
With Katie Boulter, Jodie Burrage, Harriet Dart and Heather Watson also in the team, Lumsden is unlikely to feature in a match, but it will still be a very proud moment for her family in the stands at the Copper Box.
“They’re going to come down to watch the tie,” she said. “I think everyone’s very happy, everyone close to me that saw those tough moments. It feels like a great turnaround.
“When things are tough at tournaments, I try to remember that they were a lot tougher before.”
Lumsden was one of Britain’s most promising juniors and had hoped for a top career in singles but, with her doubles ranking now at 74, making her Britain’s number one, her focus has switched.
The less physically demanding form of the sport has also proved a better fit, with Lumsden still wary of over-extending herself.
“When I was coming back, I was picking up small injuries, I guess because I was out for such a long period of time,” she said.
“Doubles definitely suits that a lot more. It’s easier physically. I can manage the loads more. Sometimes I still have a little bit more fatigue than I think’s normal. I am still careful with my training, I don’t push it too much.
“That was one of my goals for this year…just to try to do everything I can to stay healthy, to get a full season.”
Lumsden has formed a very promising partnership with fellow British player Naiktha Bains, and the pair will look to build on their progress in 2024.
Their run at Wimbledon made them the first all-British duo to reach the last eight of the women’s doubles for 40 years and Lumsden said: “It’s been really exciting.
“Having that breakthrough at Wimbledon was great, just allowing us to play in those bigger WTA tournaments. That changed the rest of the year. It’s been great to experience all these new things.”