To echo the other posters, DO NOT use basic strategy exclusively in tournament play. You're not competing against the house, you're competing against other players. I've played in tournaments in Vegas, but never on line. Don't know if you can see how the other players are doing on line, but that is key. Much of the strategy will come into play late in the tournament. If you're down against the other players and it is late, then you have to think about doubling hard cards, splitting 10's etc. Likewise, if its late and you're up, then you should consider playing conservatively, especially knowing that the other players will be taking more chances and playing more aggressively (and thus more likely to bust or get bad hands). There are numerous websites that offer strategy for BJ tournament play. Bottom line is that it really is a different animal than typical BJ play. If you only follow basic strategy, there is virtually no way that you can win a tournament.
By the way, I'm certainly no expert. I have played in 2 BJ tournaments in Vegas, and not done well in either. It was just too hard for me to adjust my style of play when I am so used to playing basic strategy. Mentally, doubling a hard 13 against a dealer 6 doesn't come easy, but sometimes that is what makes sense if you want to have any chance. If I get invited to another tournament, I'm going to study up some more and try to put basic strategy out of my mind, especially if its late and I am behind.