3. Team A and Team B each send out 5 players to participate in a chess broadcast tournament according to a pre-arranged order. The two teams first have their No. 1 players compete; the loser is eliminated, and the winner then competes with the No. 2 player of the losing team, …, until all players of one side are eliminated, and the other side wins. The sequence of wins and losses of the players thus forms a match process. Given that there are no draws in each match, how many possible match processes are there?
3.252 .

Due to the tournament rules, the first team to achieve 5 victories is declared the winner, even if some players have not participated. However, we can consider the players who did not participate as having lost. Thus, we get a complete ten-game result for one side: five wins and five losses. A match process, in this context, is how to arrange a team's five wins and five losses.
In ten slots, filling in 5 wins can be done in $C_{10}^{5}=\frac{10 \times 9 \times 8 \times 7 \times 6}{5 \times 4 \times 3 \times 2 \times 1}=252$ ways.