Lionel Messi has admitted he has endured a difficult period away from football after inspiring Argentina to victory over Algeria with the first World Cup hat-trick of his remarkable career.The Argentina captain appeared emotional after curling home a superb opener in Kansas City before going on to complete a treble in a 3-0 win that kickstarted his nation's title defence in emphatic fashion.Messi, who turns 39 next week, was at his mesmerising best throughout the contest and found the net four times in total, though an early effort was ruled out for offside.Watched from the stands by wife Antonela Roccuzzo and their children, the Inter Miami star produced another performance to underline his determination to add to the World Cup crown he won in Qatar four years ago.TRENDINGStoriesVideosYour SayHowever, after the match, Messi revealed he has recently faced challenges in his personal life, though chose not to disclose any further details."The truth is, it's something completely unrelated to sports," Messi said."I had some difficult, complicated days, but I'm grateful to the entire delegation, to all my teammates because they were always by my side, as always, giving me a lot of strength to be okay, and that's all."Messi declined to elaborate on the nature of the difficulties and instead focused on the joy he continues to experience representing his country.The evening was another memorable one for the eight-time Ballon d'Or winner.Not only did he register his first World Cup hat-trick, but he also won his 200th cap for Argentina and moved level with former Germany striker Miroslav Klose on 16 World Cup goals.Messi now has the opportunity to become the outright leading scorer in the tournament's history during Argentina's remaining group-stage matches."Like I say, everything I'm experiencing now is amazing," he said.LATEST SPORTS NEWS:Lionel Messi gives emotional speech after making World Cup history in Argentina win over AlgeriaBBC axes legendary Wimbledon pundit from lead commentary coverageThomas Tuchel will only sing England national anthem on one condition ahead of Croatia opener"I was lucky enough to achieve all my dreams, at a level, or even more, than I could have reached individually and as part of a team."Today I'm enjoying this, being part of a wonderful group, feeling good, and thankfully, being able to enjoy it on the field the way I've always loved to."And honestly, everything I've experienced is so much more than I could have imagined when I was a kid."Messi also opened up on his admiration for retired tennis great Rafael Nadal, admitting he sees similarities between himself and the Spaniard."I love playing football, it's been my passion since I was little, and when I'm feeling good I give it my all," he said."We're watching Rafa Nadal's series now and I identify with him a lot."I think we're very similar in that sense, that I always want to give my best, I always want to feel good and I enjoy it that way, and well, as long as I can and I'm fit to do it, I'll do it."For now, though, Messi's attention will remain firmly fixed on Argentina's quest to retain the World Cup.Their next match will be against Austria on Monday (6pm).After that, they'll do battle with Jordan on Juny 28 (3am). Our Standards: The GB News Editorial Charter