Answer: This is possible, if both the teams had their win percentage to be less than 50 % before the series and they each won 2 watches is in the series.
For example, let us assume both the teams to have a win percentage of 40 % before the series.
In this game series of 4 matches, each won 2 matches, so their win percentage for this series would be 50 %.
Therefore, their overall percentage will increase