How to accept a rematch offer

I just won a game through a couple of premoves, and my opponent offered a rematch.

When I logged in to see the game, I see "Rematch offer sent" in the chat room. Ok, and depending on which way I opened the link, I can see the Rematch button fading in and out, and the mouseover text says "Your opponents wants to play a new game with you"

But if I click on that very prominent rematch button, it seems to act like I'm the one who is asking for a rematch, and it waits for my opponent to accept.

Is there no way to accept the rematch that was offered by my opponent?

Is there a way to challenge or offer rematch to opponents at arena tournaments? I mean when I see players waiting for a game and it takes lots of time to get automatically paired. Also some players decide to milk the clock one move before checkmate. It would be nice to be able to start another tournament game while waiting for the opponent to move and checkmate using a premove.