Real Madrid star Cristiano Ronaldo scored the only goal of the game at the Spartak Stadium in Moscow just a day after he was summoned to appear in a Spanish court over allegations relating to tax fraud.

The World Player of the Year headed home Raphael Guerreiro's lofted cross at the far post after just eight minutes.

It could have been 2-0 in the 50th minute but a sublime one-handed save kept out Adrien Silva's header.

Portugal did struggle to add to their tally and were nearly made to pay in the closing stages.

Russia's Georgy Dzhikiya headed narrowly over in stoppage time as Ronaldo's 74th international goal proved decisive.

In today's second match, Mexico come from a goal down to beat New Zealand at the Fisht Olympic Stadium in Sochi.

Leeds United striker Chris Wood put the Kiwis ahead after he was found by a delightful through pass and slotted the ball into the corner.

Mexico were level after 54 minutes though when Raul Jimenez turned and fired a shot from the edge of the box into the far corner.

The comeback was then complete on 72 minutes when Oribe Peralta saw a first-time finish go in off the woodwork after a cut back from the left by Javier Aquino.

Following today's matches, Portugal and Mexico both sit on four points with Russia on three and New Zealand, who have gone out, on zero.

Action is due to continue tomorrow with the second round of fixtures in Group B.

World champions Germany play Chile at the Kazan Arena while Australia meet Cameroon at the Krestovsky Stadium in Saint Petersburg.

The tournament is traditionally used as a warm-up for the following year's World Cup and features the home nation, the winners of six continental tournaments and the reigning FIFA World Cup holders.