Alex Davies's late penalty rescued London Welsh from a Challenge Cup defeat against Cavalieri Prato.
Daniel George's try, converted by Gordon Ross, gave the Exiles an early lead which was extended by Joe Ajuwa.
Ross added a penalty but missed two kicks before Denis Majstorovic went in for the hosts before half-time.
Ajuwa added a second but tries by Billy Ngwaini, Niccolo Tempestini and Giacomo Bernini, all converted, put Prato in front before Davies stepped up.
Cavalieri Prato: Berryman, Tempestini, Vezzosi/Ngawini, Majstorovic, McCann, Sepe, Della Rossa, Patelli, Pelizzari, Petillo, Saccardo, Bernini, Cavalieri, Roan, Giovanchelli, Borsi.
Replacements: Cannone, Balboni, Boscolo, Ruffolo, Frati, Vezzosi/Ragusi, Tempestini, Garfagnoli
London Welsh: Davis; Ajuwa, Jewell, Whatling, Smith; Ross, Runciman; Bristow, George, Bateman; Kulemin, Purdy; Williamson, Hills, To'oala.
Replacements: Briggs, Moss, Ion, Brown, Denbee, Keyte, Davies, Scott.
Referee: Leo Colgan.