When the Japanese Davis Cup side upset Australia in 1971, Sakai played a large role, winning both of his matches, over Colin Dibley and the deciding fifth rubber against John Cooper.

[3] At Wimbledon in 1973, Sakai was eliminated in the third round by Ilie Năstase, having earlier secured wins over Frew McMillan and Hans Kary.

[3] In Osaka later that year, he beat Željko Franulović in the semi-finals to make it into his first Grand Prix final, which he lost to Ken Rosewall.

[2] He had his best Grand Slam performance at the 1974 French Open, where he reached the third round of the singles draw and was a quarter-finalist in the men's doubles, with Kenichi Hirai.

[3] The same player partnered Sakai in the Düsseldorf Grand Prix tournament that year and the pair finished as runners-up.