The No. 10 is playing at the top of his game right now and no team has been able to get near him so far at this Copa America Centenario - can anybody deny them in the final?If Tata Martino really was concerned about Argentina’s occasional defensive frailty ahead of their Copa America Centenario semifinal against the United States, he need not have been. He has Lionel Messi.The Barcelona forward has been at the heart of everything his country has done during his relatively limited time on the pitch so far this summer. That stunning hat trick in Chicago - scored inside 19 minutes - the fine assist and his record-equaling goal against Venezuela in Foxborough on Saturday.Here, at NRG Stadium, he has put Argentina in its third major final in three years following a 4-0 win over the U.S. national team on Tuesday.His assist for Ezequiel Lavezzi was excellent in its own right, but - if it’s a competition - was perhaps not quite as good as the one he laid on for Gonzalo Higuain in the last round. But his free kick, which made it 2-0 and essentially ended the game after 32 minutes, was maybe one of the best goals he has ever scored.His set piece against Panama in the group stage, the second goal of his treble, was brilliant. Textbook. Against Bolivia, from a wider angle, he almost defied logic by whipping one into the far corner. That whistled centimeters past the post. Here, he surpassed himself. Just to the left of center, more than 25 yards out and with the left-hand side of Brad Guzan’s goal gaping, he elected to go the other way. He shocked us. Wrapping his left boot around the ball, he went to the right-hand side, the one Guzan was covering, and managed to beat the U.S. keeper by squeezing the ball in that minute gap between glove and the crossbar, grazing the woodwork as it went in. It was beautiful.It was also the goal which put him out in front as Argentina’s all-time leading goal scorer. Coming into this tournament he was four behind Gabriel Batistuta, whose record has stood for 14 years. The hat trick moved him to within one. In his last match, he put the ball between goalkeeper Dani Hernanez’s legs to move level. Barely half an hour into this game he broke it, obliterated it, with a goal which would have been remembered for years to come even had it come in a friendly. Of course, it put his side into the Copa America final.Whoever Argentina faces on Sunday, be it Colombia or Chile, they should be very afraid. Messi is playing at the top of his game right now and there are no signs that anybody is able to live with him. Indeed, few teams have been able to cope with him in this kind of form since over the last decade.Ahead of this match, Martino was at pains to point out that his men ‘are not the best’ in terms of pressing from the front or building up from the back. He was concerned about a sloppy 15-minute period against Venezuela, and what would happen to them if they were as careless against the States.There was excellent backing for the hosts, too. Over 70,000 people filled out the NRG Stadium in Houston and the atmosphere promised to be electric, especially after a stirring rendition of the home national anthem. But that was all but extinguished after just three minutes when Lavezzi headed in from Messi’s chipped ball over the top. It unraveled from there, and Higuain made it 0 shortly after halftime to really hammer home the dominance. And Messi, bearing down on goal with four minutes to go, could have added to his tally, but elected to square it to Higuain for a tap-in.The U.S. was out of the game long, long before that, and it did not even register a shot on target all night, much to the frustration of the crowd.The Americans came into this game with Jurgen Klinsmann insisting he would attack Argentina. They did not have the chance. The German coach also suggested the job his men did against Cristiano Ronaldo at the World Cup two years ago should stand them in good stead to stop Messi. Cristiano Ronaldo, though, was clearly unfit and should probably not have played in Brazil at all. And he still provided a last-minute assist. Messi is fully fit after his pre-tournament set-back and is, quite simply, on another level right now.Whether it’s Colombia or Chile up next, Argentina should face its hardest test of the Copa so far. Both teams kept Messi quiet (enough) in last year’s edition as both matches went to penalties. But while Messi did play an influential role in the route to the final, as he did in Brazil the year before, he was not playing anything like he is now.U.S. soccer fans have gone crazy for Messi these past three weeks, and he is living up to his ridiculously high billing. They have demanded a show and he has given them one. Unfortunately for those supporters, they did not want one tonight but they got one anyway. He showed no mercy.Argentina is now within 90 minutes of winning its first major trophy since 1993. Martino may be worried about his team’s deficiencies, but not as much as Jose Pekerman or Juan Antonio Pizzi will worry about Messi. Can anybody stop him?