Katarina Johnson-Thompson believes winning the Commonwealth Games heptathlon, her first senior outdoor title, will inspire her to greater glory but it was a gold medal wrapped in caveats.

Of immediate concern was the calf injury that left her grimacing round a lap of honour and limping on to the medal podium uncertain of the long-term prognosis. The winning score of 6,255 points, more than 400 down on her personal best, means questions also remain over her ability to beat the best in the world over seven events. But – as is so often said – you can only beat what is in front of you and she did what was required.

The field here was of such a standard that the pressure was off, her closest rivals on paper, Nina Schultz of Canada and her English team-mate Niamh Emerson, ranked 40th and 41st in the world last year. Johnson-Thompson knew a leaden performance was good enough for gold on the Gold Coast.

Going into the 800m, the final event of a gruelling two days, the 25-year-old had a 14-second buffer between herself and the next best. Struggling with her right leg, she laboured to fourth place in her heat in 2min 21.24sec. After the line she collapsed to the track in obvious distress as her competitors offered their congratulations.

“It was the emotion and the pain,” she said, “Just after the 200m [at the end of day one] I could feel something and it worsened in the long jump. I just managed it and got through it. I thought it was under control until 300m into the 800m I felt it worsen. I thought about stopping and just carried on.”

Even before injury set in, an absence of serious competition did not seem to free Johnson-Thompson to challenge her personal best marks. A series of meltdowns at major events have seen the Liverpudlian fail to deliver on her enormous potential. The highest-profile mental collapse was three fouls in the long jump at Rio 2016 that meant she crashed out of medal contention. After that disappointment, she proved her commitment to the sport by moving to France and changing a training set established since childhood.

Since then she has won two major titles in two months, becoming world indoor pentathlon champion in Birmingham in March, but it remains to be seen whether she has fully cleared those psychological barriers. In the shot put she fouled her first throw, chucked from a standing position with her second effort in order to get a mark on the board and improved to only 11.54m.

Despite an underwhelming overall score, the title puts her in illustrious company with the 2000 Olympic champion, Denise Lewis, and the three-time Olympic medallist Kelly Sotherton among the former winners. With a gold medal round her neck, Johnson-Thompson extracted the positives. “I haven’t set the world alight with my performances,” she said. “But I’m so proud of myself that I came here and made season’s openers and season’s best off not a lot of training. I’ve been competitive, got a gold medal – the second of the year – and I have 16 weeks to build on this and get ready for the Euros.”

She has her sights set on a treble but at the European Championships in Berlin in August she will face significantly tougher opposition. The Olympic champion, Nafi Thiam, will head up a field including Carolin Schäfer and Anouk Vetter, who completed the podium at last year’s world championships in London.

“My aim this year was to build a winning habit,” she said. “I’m two-thirds of the way there. The treble is a big ask. I said that I wanted to win two golds, I’ve done that. I want to win three medals.

“It’s all coming together and the more I compete, the more I expose myself to things like this, the more I learn. I’ve got tough competition in the Europeans, I might not be going in as favourite but I’m a grafter.”

The minor medals went with the formbook as Schultz took silver with 6,133pts and the 18-year-old Emerson bronze with a personal best of 6,043.

Caster Semenya won the 800m in a Games record 1min 56.68sec to add to the 1500m title claimed on Tuesday. The South African’s victory looked assured from the bell and the double Olympic champion suggested that after the Tokyo Olympics in 2020 she might consider competing in distance events. “For these four years the target is to double at every championship,” she said.

“We need to run four championships doubling and then decide if we still have speed for 800m. If we still have speed in 800m then we will continue with the 800m. If not, we will go further, because obviously there is 5,000m and 10,000m. I believe I can do better in the future. I’m only 27. When I do my long runs I feel I can feed into distance running. For me, this is more than a game.”