Portugal forward Cristiano Ronaldo has clearly seen better days, but though he became the first to reach the milestone of scoring in five men's World Cups, with a highly dubious penalty in the 3-2 win against Ghana, the evidence of the game was that there are still moments when the 37-year-old offers a potent threat at this level.

But does the same apply to the centre forward that Portugal will likely be facing in their second group-stage game on Monday? Luis Suarez is Uruguay's all-time top goal scorer, but his performance in the 0-0 draw against South Korea was not impressive. He touched the ball 18 times, losing it on nine of those occasions, and did not manage a single shot on goal.

Approaching 36, it is hardly surprising that Suarez is in decline. True, he was Uruguay's top scorer in qualification with eight goals, but five of those came from penalties. Suarez was replaced after an ineffective hour against South Korea and the time may have come to think about starting Monday's match without him.

Ever since Russia 2018, Uruguay have sought the holy grail of integrating their new generation of stars with the old stagers. The balance has so far proved elusive -- hence the problems in qualifying, when it took a change of coach and a late surge to carry them over the line.

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There is a key structural problem. The midfield, at least in potential, is now the best part of the team but it functions better with three in the centre -- Matias Vecino and Rodrigo Bentancur to protect the defence, link the play and free Federico Valverde to use his lung power, technique and excellent long-range shooting. However, having a central midfield trio makes it hard to play two up front, and this is a seismic change for a team which for years has paired Suarez with Edinson Cavani in a 4-4-2 formation. The picture is further complicated by the rise of Liverpool's Darwin Nunez as another powerful centre forward option.

Cavani, ever the team man, appears to have accepted a place on the bench now he is 35 years old, and space has been found for Nunez, as it was against South Korea when he operated from the left flank in a 4-3-3. But other options are available. But what if the young and dynamic Nunez were to play up front on his own in the centre forward position? He would certainly offer more mobility than Suarez, and he might hold up the ball better than the veteran managed on Thursday.

In turn, this would free up space for another type of attacking talent. Playmaker Giorgian De Arrascaeta did not get on the field against South Korea and throughout the eight years of his international career to date there has always been a feeling that he did not fit into a 4-4-2 formation which sends him out to the wings, where he is not quick enough to thrive. But centrally, behind a lone striker? That might work better -- for him or for Facundo Torres, the latest playmaking talent off the block.

It would be a huge call for coach Diego Alonso to leave Suarez out of the starting lineup for Monday's game, but there would be some logic in the decision.

Portugal are a team who move the ball well; running power and closing them down as they play out from the back, will be important. And there is perhaps a wider point. This tournament, and especially Japan's thrilling 2-1 win over Germany, has made something very clear: Football is no longer a sport for 11, or even 12 or 14 players. With five substitutions no available, teams are made up of 16, and the ability to change the course of the match by going to the bench is now important.

Joining Cavani on the bench should be no humiliation for Suarez; he could still have a key role to play. Imagine that Uruguay are behind and chasing the game. In that scenario, circumstances would demand that the team push high up the field, where Suarez's penalty-area nous and finishing skills could save the day.

Over the years Ronaldo has accepted that in order to stay at the top he has to operate in reduced space. Perhaps in the current Uruguay side the 2022 version of Suarez needs to operate in reduced time.