Larson, the reigning Cup Series champion, went out late in the 35-minute session for a flying lap and posted an average speed of 181.183 mph. Larson won the first of his 10 races last season at Las Vegas.<br>Christopher Bell ended up second-fastest (180.771 mph) and Ryan Blaney third (180.000 mph.) William Byron was fourth and Joey Logano rounded out the top-five.<br>Read Also:<br><br>NASCAR Cup ...<a class='more' href='https://www.motorsport.com/nascar-cup/news/kyle-larson-fastest-vegas-cup-practice/8730971/?utm_source=RSS&utm_medium=referral&utm_campaign=R SS-NASCAR&utm_term=News&utm_content=www'>Keep reading</a>

More...