Career
At the 1973 French Open, Borisov competed in both the men"s doubles (with Viorel Marcu) and mixed doubles (with Natasha Chmyreva), but was unable to progress past the opening round in either. His only other Grand Slam appearance came in the 1976 Wimbledon Championships, where he lost in the first round of the singles draw, to Kenichi Hirai. He also played in the mixed doubles, again partnering Natasha Chmyreva and once more lost in the opening round.
In 1980, Borisov was runner-up in both the singles and doubles at the Sofia Open, which was part of the Grand Prix tennis circuit.
His singles wins were over Leo Palin, Ismail El Shafei, Andrei Dîrzu and Louk Sanders. Singles: (1).
