Three observations from Wednesday's World Cup action

It was three of the world's top marksmen who did get on the scoresheet, though, as Cristiano Ronaldo and Diego Costa continued their fight for the Golden Boot, while Luis Suarez scored in his third World Cup.

We look at three things we learned today at the World Cup.

Ronaldo eyes more gold

Few goalscoring titles still elude Ronaldo and he may soon have one more to add to his collection after netting for the fourth time in two games against Morocco to move out in front in the race for the World Cup Golden Boot.

Ronaldo has now already scored more goals in Russia than his three previous World Cup campaigns.

Having spearheaded Real Madrid's run to a third consecutive Champions League, Ronaldo's fast start to the tournament also puts him in pole position for a sixth Ballon d'Or -- to finally move ahead of Lionel Messi's five.

Messi missed a penalty in Argentina's opener, while fitness issues for Neymar and Mohamed Salah have blighted their challenge to Ronaldo's crown.

The competition is not even a week old, but the World Player of the Year's message is clear: "Catch me if you can."

Uruguay, Russia roll on

They did it in very differing fashion but Uruguay and Russia became the first sides to book their places in the last 16 after the South Americans edged past Saudi Arabia with their second 1-0 win of the tournament.

By contrast, Russia have been rampant in scoring eight goals to reach the knockout phase for the first time since the Soviet era.

Blessed with one of the most feared strike forces in Russia in Suarez and Edinson Cavani, more was expected from the Celeste against a Saudi side that shipped five to Russia in the tournament opener.

However, Uruguay know how to negotiate their way through a tournament under 71-year-old Oscar Tabarez and with Atletico Madrid duo Diego Godin and Jose Maria Gimenez marshalling their defence, they will be a tough opponent for, most likely, Spain or Portugal in the last 16.

Spain glad to have Costa

Since switching allegiances from the country of his birth, Brazil, to play for Spain ahead of the 2014 World Cup, Costa has not always seemed the perfect fit for La Roja's tiki-taka style.

So far in Russia, though, Costa is keeping Spain afloat by adding a dimension to their play not seen in past tournaments

He bullied Pepe and fired home from close range at the end of a well-worked set-piece to score a double in a thrilling 3-3 draw against Portugal.

And Costa moved to within one goal of Ronaldo in fortunate fashion as a clearance ricocheted off him and into the Iranian net as Spain survived a huge scare in Kazan.