Portugal are the defending FIFA Beach Soccer World Cup champions ©Getty Images

Defending champions Portugal opened their account at the FIFA Beach Soccer World Cup with a victory over Portugal in Group D, but there was a shock in Group C as Switzerland beat Brazil on penalties.

Leo Martins grabbed a hat-trick for the Portuguese as they eventually triumphed 5-3 against Oman.

The group is topped by Senegal, after they thrashed Uruguay 6-1 to record the biggest win of the opening round of fixtures.

The African champions cruised to victory, with Raoul Mendy grabbing a hat-trick and Mamadou Sylla, Ninou Diatta and Mamour Diagne also on the scoresheet.

In the final game of the day at the Luzhniki Beach Soccer Stadium in the Russian capital Moscow, five-time champions Brazil were beaten 4-3 on penalties by Switzerland after a 5-5 draw.

This was Brazil’s first-ever defeat in their opening Beach Soccer World Cup match, having won the previous 11.

Brazil had beaten Switzerland in the 2009 final, but were on the receiving end of a penalty shoot-out defeat by the Swiss in today's opener ©Getty Images
Brazil had beaten Switzerland in the 2009 final, but were on the receiving end of a penalty shoot-out defeat by the Swiss in today's opener ©Getty Images

Dejan Stankovic won the Golden Ball at the 2009 World Cup as the Swiss lost to Brazil in the final, but was on target twice in normal time and in the shootout in Moscow.

The other Group C game saw North and Central America and Caribbean champions El Salvador beaten 5-4 on penalties by Belarus, after a 5-5 draw.

The second matches of Groups A and B take place tomorrow, with the Football Union of Russia hosts playing Paraguay in the last match of the day in group A.

The United Arab Emirates will seek their second consecutive win against Mozambique in the first match in Group B, with finalists in 2015 and 2017 Tahiti looking to bounce back from a defeat to the UAE when they face Spain.

Japan take on the United States in the day’s other match in Group A.