She achieved a career best for the half marathon at the Rome-Ostia race in February 2005, running 1:13:15 and finishing as runner-up to Rosaria Console. Another best came at the Turin Marathon in April, where her time of 2:33:16 brought her fourth place. Her performances gained Mancini her first national selection – at the 2005 IAAF World Half Marathon Championships she ended the competition in 51st place. She ended that year with a fourth-place finish at the Venice Marathon.