In most international soccer competitions, tournament structure calls for a two-game series to decide each round. Sometimes called a home-and-home series, the two games usually occur during consecutive weeks; the week-long break in between games is best considered a seven day halftime separating two 90 minute halves. That D.C. United beat their opponent Pachuca C.F. last night offers scant consolation to their fans. Factoring in Pachuca’s 2-0 victory last week, United’s 2-1 win last night…