TOKYO, July 28 (Reuters) - Canada claimed their first men"s volleyball win at Tokyo 2020, overcoming Pool A"s in-form team Iran in straight sets, while hosts Japan were beaten for the first time as Italy put in a solid performance to triumph in four sets. Having lost to Italy and Japan in their previous outings, Canada were quick off the blocks, capitalising on a slew of errors from Iran to take the opening set comfortably. The second and third sets were closer but, courtesy of John Perrin"s 16 points and Nicholas Hoag"s 15, Canada steadily built their lead with a combination of spikes and blocks to win 25-16 25-20 25-22. "I"m really happy with our first win in the Olympics. We played well, especially with many blocks. It wasn"t a game plan but more our ambition to block," Perrin said. "(We) keep believing that we are going to make it into the playoff and medal rounds, that"s our goal... I feel like what we"ve given isn"t exactly what we"ve gotten back in our standing." Japan coach Yuichi Nakagaichi had said that they had never beaten Italy when Osmany Juantorena and Ivan Zaytsev were on the other side of the net and so it proved again as Italy won 25-20 25-17 23-25 25-21 to dislodge the hosts from top spot in Pool A. Juantorena and Zaytsev had 22 and 18 points respectively while Alessandro Michieletto had 16 but it was Italy"s 13 blocks and Japan"s errors that made the difference. "We had many serve errors," Yuki Ishikawa, Japan"s top scorer with 22 points, said. "I believe that our team can get points in clutch moments. There were several moments we were behind Italy by many points, but we played patiently and almost caught up with them." Poland took top spot in Pool A with a 25-16 25-13 18-25 25-15 win over Venezuela. ROC REMAIN UNBEATEN The Russian Olympic Committee (ROC) are the only side to remain unbeaten after three rounds after a straight sets victory over world number one Brazil. Outside hitter Dmitry Volkov was again the man to rise to the occasion with 19 points and four blocks while Maxim Mikhaylov had 15 as ROC won 25-22 25-20 25-20. Earlier, the U.S. beat Tunisia 25-14 23-25 25-14 25-23 with Torey Defalco scoring 24 points. The Americans were formidable in defence with 41 successful digs while their back row attacks also proved too good for Tunisia. Argentina also won their first match after two losses, edging France in a five-setter to win 23-25 25-17 25-20 15-25 15-13 as four players finished in double figures, led by Bruno Lima (18 points).