Write about what you know… or not

I got this fantastic idea for a story (one I thought was fantastic, anyway) about a tennis player and his PR Exec heroine. 40k in and there are a lot of notes left through the wip going something like ‘research’, ‘how can you not know this?’ ‘more research’.
The problem is, though I watch the sport I know NOTHING about it, not even the scoring system. Of course, it’s a romance, I really didn’t think this was a problem.
I was wrong.
Until now, I’ve penned books about topics I’m at least a little knowledgeable about. I read up on Fashion Week because I like seeing what the latest trends are – so A Week in Milan was easy. I adore movies and also read the gossip rags so writing a behind the scenes love affair (Isle of Sensuality) was pretty easy too. Even Paris & Nicole’s TV series gave me an incline of how a hotel heiress would be, though Alexa from Sinfully Summer doesn’t live up to anyone’s expectations.
Sebastian Collins is a bloody nightmare. He’s been through a bad split, his ex is using his fame to her advantage and selling kiss-and-tells. The British (and international) press are pushing these stories and the stress is getting too much for him. He’s flunked out of a major tournament and his sponsors are getting cold feet.
The worst part? He's now very focused on his career, a career I knew very little about. 
I’m now putting in the time to learn, just in case I’ve missed anything crucial that might alter the direction of my story, although I actually never expected it to (but viola, tennis players have special diets so that pizza they ordered? Not a chance). Just goes to show a little bit of research really does help.
Pity my research is leading me astray and I find myself looking at half naked pictures of male tennis players. What do you think of him as my latest hero? He fits Sebastian to a T and has the cheeky smile to match.