Certain circumstances can delay your next opponent due to previous match issues.

Previous match timer was extended
Previous score wasn't reported or accepted
Previous match expired awaiting admin ruling
Player hasn't shown up


Feel free to click on the "View Bracket" and find the match you're waiting on.  Then head to the chat and ask them to get their match played or who won.  If it's expired an admin will be notified and get to it ASAP.