Lionel Messi insists he is a one-club player ahead of Barcelona's Champions League semi-final first-leg encounter against Chelsea.The Argentinian is arguably the most potent threat which the Blues must stop when the teams clash in the Nou Camp on Tuesday.These skills mean the 21-year-old is much sought-after by clubs throughout the world but he insists he wants to spend his entire career at Barcelona, where he made his debut aged 17 and who paid for his treatment for growth hormone deficiency.He told the News of the World: "To be honest, every time I get asked this question I find it very boring."I have said many times I intend to stay with Barcelona until I retire. I know a lot of players say this, but I really mean it. You have seen how well we have been doing and you have seen the way we play football - why would I want to leave?"There are a lot of smiling faces in our dressing-room. There is no reason for me to ever want to leave."I am loyal as well. I am aware that I owe Barcelona a lot. They gave me a chance and now I want to reward them with even more success."But he knows it will be tough against Chelsea and singled Frank Lampard out as a player he admires."Even though confidence is high, we are aware of Chelsea's great record in Europe and we are going to need to be playing our very best in the two games to progress," said Messi."I believe Chelsea will provide the biggest test we have had so far this year in the European Cup, and we are ready for that test."We know they have a great squad that contains some of the best players in Europe, but I particularly admire Frank Lampard."To have a midfield player who consistently scores so many goals at the top level is a rare thing. It is something we need to look out for in the two matches. For sure, Frank is a big threat."I admire the way he plays the game and the way he conducts himself on the pitch."He always seems to be in the running or talked about when World Player of the Year comes along and that says a lot about him as a player."Chelsea boss Guus Hiddink concedes it will be difficult to stop Messi but insists the Blues will not resort to underhand tactics to achieve this aim.Instead Hiddink says his side must work as a unit to negate his threat.The Dutchman said: "I love the way he plays. Nature gave him a lot of gifts. Players like him make football very attractive to see."Of course we want to stop him, but we will never use means that are outside the rules or that are violent."I know it will be difficult to stop him. He is world-class. But I am not waking up in the night worrying about it."I just know that everybody in my team must be ready to mark and tackle, because Messi and Barcelona interchange positions so much. We will stop him as a team, not through any individual."