In late summer 2009, coming off a great club season at Hemofarm as well as helping Serbia win the 2009 Universiade tournament on home soil in early July, Mačvan made the Serbian national team 12-man roster head coach Dušan Ivković took to EuroBasket 2009 in Poland. Being on a young squad whose oldest members were 26-year-olds Bojan Popović and Nenad Krstić, 19-year-old Mačvan was the squad's youngest player. Despite the player's youth and inexperience at the big stage, coach Ivković gave Mačvan decent minutes off the bench at his major tournament debut game versus world champions, Olympic silver medalists, and EuroBasket runners-up Spain that Serbia surprisingly won 66-57 while Mačvan contributed with 8 points and 3 rebounds in 17 minutes of action, hitting two clutch three-pointers in the third quarter, incidentally his only field goals of the contest. The group stage continued with a loss versus Slovenia and this time Mačvan got 18 minutes backing up Novica Veličković at the power forward position as his scoring output dropped off to 4 points. In the second group stage outings — wins against host Poland followed by a loss to Turkey — Mačvan's playing time decreased, before getting a slight bump versus Lithuania in the closing group stage contest while his scoring contribution became almost negligible. At the first single-elimination stage, quarterfinal win versus Russia, the youngster's game saw a slight boost with 5 points, though this was followed by a complete omission in the hard-fought semifinal overtime win versus Slovenia as Ivković preferred the more experienced Veličković. In the final the next day, tired and emotionally spent Serbian team lost big to Spain with young Mačvan getting little opportunity to play.