Gretta came in second place at the 11th Asian Junior Athletic Championships in the 200 metres. She competed at the 2001 World Championships, the 2003 World Indoor Championships and the 2004 World Indoor Championships, where she set the indoor 200 meter Lebanese national record at 25.80. She set a new national record in the women's 200 metres at the 2004 Summer Olympics, but came in last in her preliminary heat and did not advance.