Novak Djokovic has joined Roger Federer in the Italian Open semi-finals with a 6-3 3-6 6-1 win over Kei Nishikori.
The defending champion will play seventh seed David Ferrer, who defeated David Goffin 6-2 4-6 6-3.
Federer cruised to a 6-3 6-3 quarter-final win over Tomas Berdych as the second seed kept alive his hopes of an elusive Italian Open title.
The Swiss, 33, will face either seven-time Rome champion Rafael Nadal or Stan Wawrinka, who meet later on Friday.
Rome and Monte Carlo are the only two Masters series titles that the 17-time Grand Slam champion Federer has never won.