Count Matches, Not Games

I have a spreadsheet that is used to track stats during a tournament. In the past we have always used a number of games as the minimum before a team's rating can change. We would like to change it so it's a minimum number of matches instead. A match can be as few as 2 games and (currently) as many as 7 games. If you look at the sample spreadsheet I've attached, the match data starts in column J. I've marked the top of the sheet to delineate matches but I'm not sure how the count the number of unique matches. The formula should be (for the first team) in E5. I've filled in that cell for the three examples. Any help would be greatly appreciated.