I'm not gonna lie, I really wanted to pick Jay Garrick because in comics Garrick was the first Flash (as on CW?) and of course portrayed by John Wesley Shipp who has the distinction to play 2 Flashes on TV in one lifetime. Among other reasons.
That said, before Crisis Jay was retired, and unless confirmed otherwise, if he survived the Crisis Jay is still retired. Although not the best argumnent, Garrick might not be as powerful to beat the Scarlet Speedster.