Zhang Zhizhen becomes China's first man in tennis top 100
The 26-year-old would have been guaranteed to make history had he beaten American McDonald but results in other tournaments ensured he made the top 100 regardless of his 6-4, 3-6, 2-6 defeat in Italy.
Contacted by AFP, the ATP confirmed that Zhang can fall no lower than 100 and as of Friday is projected to be world number 97 once the rankings are published on Monday.
Zhang started this week at a career-high 109 in the world and was bidding to become the second Chinese man to reach a tour-level semi-final in the open era - or since 1968 - after Pan Bing in Seoul in 1995.
However he was almost sure to arrive in the top 100 just by making the last eight as he would have needed a series of players to either win titles or make finals this week to stop him reaching a landmark ranking.
Chinese women have long been high ranked with Li Na winning the French Open in 2011.
Naples troubles
Zhang's achievement is probably the highlight so far of a tournament in Naples which has experienced difficulties right from the start.
The weekend's qualifying matches were moved to another tennis club 20 kilometres away in Pozzuoli and played behind closed doors after players complained about the hard court surface in Naples, which turned out not to be waterproof.
The court used at the previous week's tournament in Florence was then taken down to Naples, while matches were played both there and in Pozzuoli, leading to Adrian Mannarino playing matches in both venues on Tuesday.
Zhang, who played in those troubled qualifiers to make the main draw, had to win two matches on Thursday to reach the quarters, beating both Marton Fucsovics and sixth-seed Sebastian Baez in straight sets.
McDonald will face home hope Matteo Berrettini in the Naples semis after the Italian beat Japan's Taro Daniel in straight sets 6-2, 6-3.
