Caster Semenya stormed to a record-breaking Diamond League victory in Stanford with her future still up in the air.

Semenya clocked the fastest 800 metres time by a woman on American soil of one minute, 55.70 seconds on Sunday.

The South African was competing in the Diamond League for the first time since being cleared to run by the Federal Supreme Court of Switzerland (SFT), as she awaits the outcome of an appeal in her case against the IAAF.

The double Olympic 800m champion is challenging the IAAF's decision to introduce restrictions on testosterone levels in women competing at distances ranging from 400m to a mile.

Semenya appealed to the SFT after the Court of Arbitration for Sport (CAS) ruled that the IAAF could implement the regulations.

The 28-year-old did not run in the last Diamond League event in Rabat, although she denied declining an offer to race after initially being denied entry before the SFT declared she is free to run without restriction until a verdict is reached.

Semenya took the bell in 57 seconds and powered away from the pack for a dominant victory ahead of Ajee Wilson, with Raevyn Rogers third.