Clinchers, Tubeless and Tubulars (there are others...). It depends on what kind of race. I can see a steady velocity case for tubeless. They seat very well, have low rolling resistance.
The tubular setup is going to be lighter for same tire, turn better and be less puncture prone. They may have slightly higher CRR, but a lot of that is how well they are glued. And, you have to know how to glue them.
There is stuff made in tubular that is just not available, or tested in clincher. I have not test data (see last sentence) but I'd be very surprised to see anything beat a nice silk tubular in any category but price and water.
I am not a racer and use tubulars when high durability is important - tandem. I have always fit the kid with them on his racing bikes. There are a few cases I think the tubeless might have been better, but very few.