What happened to the option of racing/challenging someone? :(
It was removed a couple of updates ago. If you backed up before updating then you may be able to recover the older version which still works.
No reason was given for removing it. I may be that it was too processor intensive so was removed for efficiency reasons or it may have been removed in order to gives us a better one (some day). Nobody really knows apart from DL staff and they have not commented.