Third-seeded Italy was upset by Iran, while the United States survived a scare from Belgium at the FIVB Men's Volleyball World Championship in Poland on Sunday.

The powerful blocking of Iran proved to be unbreakable as they defeated three-time champions Italy in their opening match 25-16, 23-25, 25-21, 25-22.

Like Us on Facebook

Iran scored 15 points off of their blocks compared to the eight of Italy. They were able to limit the Italian star Ivan Zaytsev to just 19 points, making 19 of 39 spike attempts.

Amir Ghafour led the Iranians with 18 points, 15 from attacks and three from block points.

Iranian coach Slobodan Kovac said that their success was attributed to their patience and complemented on their setters who set plays really fast.

"We've had a good reception and our setter played really fast," Kovac said. "In this case, it's difficult for other teams to play with us."

Iran will play recent World League champions USA on Tuesday.

The Iranians are tied in first place in Pool D of the tournament along with France who shut out Puerto Rico in their opening match 25-23, 25-22, 26-24.

In third place at Pool D, team USA survived a five-set thriller against Belgium 25-21, 17-25, 25-16, 21-25, 15-11.

The United States started off sluggish against the 37th seeded Belgians but eventually held on to the win as the dynamic duo of Taylor Sander and Matthew Anderson combined for a total of 36 attack points.

Gert Van Walle top scored for Belgium with 13 points.

USA coach John Speraw was not surprised with the performance of Belgium.

"We've studied Belgium and I have a great respect for them," Speraw said. "Their system of play is excellent and they have a lot of depth ... It's a dangerous team."

Defending champions Brazil will see action Monday in Pool B while China is set for their opening matchup against Egypt also on Monday.

TagsIvan Zaytsev, Amir Ghafour, FIVB Men's Volleyball World Championship, Taylor Sander, Matthew Anderson