If Argentina's Lionel Messi has anything to worry about at this World Cup it should be a goalkeeper known as "the Tarantula" he has failed to score against in their last seven clashes.Belgium goalkeeper Thibaut Courtois and Messi will have the latest of their epic battles when their countries meet in the World Cup quarter-finals in Salvador on Saturday.It is almost a David and Goliath tale. The question is, which is which?The 1.99 metres (6 feet 6 inches) tall Courtois towers over his 1.69m (5ft 7 inch) rival Messi.The Argentine winner of four Ballon d'Or awards is a giant among attackers though, scoring four times already at this World Cup.Courtois is known as "The Tarantula" because foes believe he has eight arms to keep all angles covered. And he has done it with style.Still only 22, Courtois racked up his 100th career clean sheet against Russia in their Group H match last week. He played a key role in Atletico Madrid's Spanish title-winning campaign this season, which is why his parent club Chelsea say they want him back for 2014-15. It is the matches between Messi's Barcelona and Courtois's Atletico that makes their rivalry so special.In their first meeting in September, 2011, Messi humiliated Courtois with a stunning hat-trick in a 5-0 win at Barcelona's Camp Nou stadium. The following February, a quick free-kick flummoxed the Belgian to secure victory in the return Spanish championship game. In December 2012, there was another Messi brace in a 4-1 win.Since then there have been seven games in the Champions League, La Liga and the Spanish Super Cup where Courtois and fate have denied the Argentine, leading Atletico to the Spanish title and Champions League final at Barca's expense.In two games, Messi went off injured. He slammed a penalty against the crossbar in another and in May this year got the ball past Courtois but was ruled offside.Courtois, who inspired the word 'Thibauting' when a wave of social media photos were posted of fans re-enacting his saves at home or work, remains confident of keeping up his spider's web protection."I know him well from Atletico's games against Barcelona, so it'll be nice to play against him for our countries," Courtois told ESPN television in an interview this week."The good thing is that I don't have to watch videos of him because I know him so well. But even if you watch videos of him, he's so unpredictable that it's impossible to study him to know what he's going to do."As soon as he finds a way to shoot, he will shoot, so the only thing you can do as a goalkeeper is concentrate at all times," he added."Hopefully we can win, but we'll see."Bookmakers seem to favour Messi in the match and the tournament. He is still number one contender to win the Golden Boot for the top scorer at this year's World Cup. Another part of history also favours Argentina. Belgium lost to Argentina 2-0 in the semi-finals of the 1986 tournament -- both goals coming from another golden boot, Diego Maradona.