I don't know about tennis but I placed a champions league game there and it worked really fast. I think they are upgrading their site, in fact I can see now that the login time which used to be quite some seconds is almost instant. Give them a bit more time and you will see for sure an improvement. They want to get the biggest here, they opened the signature campaign again and I think it will be running at least until winter break for the sports betting no matter them saying it's only for one month.