Zakatak I'm a noisy and intrusive extravert, but I understand pretty well how exhausting I can be for some introverts. If an introvert would want to avoid my smalltalk and social pressure coming with it, I would think that directly approaching me and humbly explaining the situation would do the trick. Saying something like "I am very sorry, You are a great guy and obviously the heart of the party, but I was born a thick introvert and this burden is mine to the grave. Unfortunately, most social communication for me is exhausting. So please don't take it as an offense if I am not communicative enough - it is REALLY difficult for me". It may sound silly - but this would work with me and I will try not to frequently overwhelm the guy.
Good luck :-)