Olympic and World track champion Caster Semenya cruised to victory in the 5,000 metres at the South African athletics championships in Germiston on Thursday.
The 5km event is a potential new distance for her as she awaits the verdict of the Court of Arbitration for Sport (CAS) in an appeal against regulations seeking to limit her testosterone level.
The 800m expert looked in complete control as she won in a time of 16:05.97 on the opening day of the championships, which serve as an important test for the South African team going to the IAAF World Championships in Doha in September.
Semenya beat fellow Olympian and defending national 5,000m champion Dominique Scott, but the latter admitted she is unsure whether Semenya could be a serious Olympic contender over the longer distance.
"Honestly‚ I have no idea‚" Scott said. "Before today I probably would have said no. It's hard to compare a 5,000 at altitude to a 5,000 at sea level.
"But I think she's an amazing runner and I don't think there's any limit or ceiling on what she can do."
Semenya made a rare run in the longer distance after earlier cruising into Friday's final of the 1,500m with a time of 4:30.65, well below her personal best.
Although she barely broke a sweat, her 1,500m time was nine seconds quicker than the second fastest qualifier. Her time was 45 seconds slower than the best mark set in 2019 so far, but Semenya looked to be holding back before putting in her familiar sprint in the final 200 metres.
Semenya is waiting for the outcome of her appeal, asking CAS to halt the introduction of new regulations by the International Association of Athletics Federations (IAAF) that would require her to take medicine to limit her natural levels of testosterone.
The IAAF wants female athletes with differences in sexual development to reduce their blood testosterone level to below a stipulated concentration for a period of six months before they can compete, to prevent any perceived unfair advantage.
But this is limited to events ranging between 400m and a mile, and so would not include the 5,000m, leaving Semenya free to compete unhindered in that distance. It does, however, rule out her primary 800m event, as well as the 1,500m race.
CAS is due to deliver its verdict on Semenya's appeal before the end of April.
Meanwhile, 400m Olympic gold medallist and world record holder Wayde van Niekerk pulled out of his heat on Thursday, citing a wet track as he attempted to resume high-level competition after 18 months out.
"We are trying to take the correct decisions now early in the year so as not to put myself in any harm," he said.
"It was a bit chilly this entire week prepping and coming through here as well it was quite cold and it caused bit of tightness in my leg. We decided to not risk it.
"My recovery is going well and I would like to be back in competition this year, but will only do so if I can deliver a good performance.
"I am a competitor and respect my opponents, so I need to be at my best when I return."
Van Niekerk injured his knee in a charity touch rugby game in October 2017 and missed the entire 2018 season.