Majchrzak was beaten 4-6, 7-6(5), 3-6 in Wednesday’s match, bowing out of the Hall of Fame Open tournament in Newport.
The 23-year-old Pole, who is 102nd in the ATP ranking, faced an opponent of such a calibre for the first time.
Isner, 11 years his senior, is 15th in the Association of Tennis Professionals singles rankings and a three-time Newport winner.
(aba/gs)
Source: PAP