Spain face Portugal Wednesday night in Donetsk. The match could be a thriller - but don't bet on anything at this stage of the European tournament.

Inarguably, the four best teams are in the semifinals; that they are also four of Europe's traditional powers, with Germany and Italy joining the Iberians on the other side of the bracket, is no coincidence. But as these Euros have progressed, there is one, inexorable truth that soccer fans are slowly waking up to: after a thrilling group stage, these teams are slowing down, exhausted by both the heat and the grueling league seasons their players have just endured.

Spain, in particular, is coming under heavy criticism for its controlling and, well, boring style of play. It is a fair knock if you care about aesthetics in this sport; if you do not and only care about results, then, yes it is hard to argue with winning. Unfortunately, beauty has always been a factor in the game of soccer - it is often reviewed on this continent with the same attention to style as is given a gallery showing or a dance recital - and Spain's slogging tactics are not making the grade.

What Spain have done of late is smother: their midfield is unquestionably the best in the game at retaining possession and they are dogged at regaining it if and when they lose it. What they have not demonstrated is the slickness and domination we have come to expect of a team comprised largely of Barcelona and Real Madrid's marquee players.

Some of their players have bemoaned the criticism, with Andres Iniesta plaintively begging fans to leave them alone and let the team show what they can do. The problem is, they have shown what they can do - win games. But that's not enough for fans of a modern attacking sport. Are a few more lovely goals too much to ask for?

Part of the issue is tactical. Coach Vicente del Bosque has his charges playing in a swarming six-man style that uses the so-called "false nine" instead of a true striker. In theory, this should clog the midfield and give Spain more avenues of attack. In practice, it has led to a constipated offense, decent enough to beat a French team that seemed eager to head for the bus only minutes after the opening whistle - but perhaps not good enough to deal with a team willing to actually run at you.

Portugal have shown they are willing to run at teams, which may give the defending champs a true challenge. While Portugal are perhaps the most unbalanced side left in the tournament, they also have the best individual player in Cristiano Ronaldo. He has been magisterial over the past two games, transforming a Portuguese side that often lags in the back into a dangerous attacking machine.

Portugal's major weaknesses are Rui Patricio in the net, and their lack of a central striker. Ronaldo and Nani patrol the wings, with the former looking far sharper than the latter, but now with Helder Postiga out (hamstring) they are even more depleted driving the lane than usual. Hugo Almeida had his chances against the Czech Republic to show us what he was made of but, despite appearances of being a superior player, he fluffed all his takes.

But Joao Moutinho and Raul Meireles have been special this tournament. Neither man has gotten a lot of credit for it, either. Moutinho is a tricky little playmaker - a type that would be right at home in Spain's midfield -- and he has been instrumental in spreading the ball about the field.

Meireles - a curiously underrated player despite being indispensible during Chelsea's Champions League trophy run - has shown both legs and vision this tournament. His passes have been crisp and he is able to spark the attack with a single lob (Holding the ball is admittedly another matter).

But it all comes back to Ronaldo, and it is not unfair to say the Portuguese will live or die by him. Against the Czechs they lived, winning with a powerful header that simply blew through Petr Cech's grasp. He was an animal that night, ferociously pulling defenders to and fro, deserving more than he got for his efforts - he has hit the post three times this tournament, twice in the last match alone.

Moreover, he has finally shrugged off some of his reputation as a choker. He has shown up in these big games and he has welcomed the burden that comes with stardom.

What Ronaldo will not ever be is beloved by fans - he is too slick, too cocky, and rubs just about everyone the wrong way. He has the misfortune not to be this age's golden boy, Lionel Messi - the little Argentine is a magician and assassin who is also curiously adorable. Against him, Ronaldo seems, well, less than wholesome.

Ronaldo doesn't seem to enjoy being Messi's foil , but someone should tell him that villains always get the best lines. He may not have all of Messi's skill but he is a consummate leader, a dogged worker and deadly with the ball at his feet. His acceleration is otherworldly and he is riding one of the longest and greatest hot streaks in the game. He will have to be considered the World Player of the Year if he leads Portugal to the final.

One would hope that these two teams could raise sparks on the field. But, if we've learned anything in these late stages it that only one side - the Germans - look like they are able to kick it into an upper gear. In the heat of Donetsk, one hopes that the free-flowing soccer both teams can offer will be on display. But, as I said, don't bet on it.