Milutin Osmajić scored for Montenegro during the international break, while Alan Browne and Liam Millar were also in action.
North End’s No.28 came on in the 61st minute of his nation’s friendly against Lebanon last Thursday and went on to score only his second international goal just eight minutes later.
Montenegro went on to win 3-2 that evening, but they were beaten on Wednesday evening in a UEFA EURO qualifier against Serbia.
Milutin was introduced from the bench in the 85th minute in Belgrade, but couldn’t help his country avoid a 3-1 defeat, which leaves them five points outside of the top two in Group G.
Elsewhere, skipper Browne started for Republic of Ireland in their qualification defeat to Greece last week.
Stephen Kenny’s side lost 2-0 on home soil, before then heading to Portugal to win 4-0 against Gibraltar in the seventh match of the qualifying campaign, however Browne was an unused substitute.
The Boys in Green are still in with a chance of making the tournament in Germany, but have work to do to catch up with France, Netherlands, and Greece.
Meanwhile, Millar travelled to Niigata with the Canada national team to take on Japan in a friendly at the end of last week.
The 24-year-old came on in the 81st minute of the 4-1 defeat to earn his 22nd cap for his country.
Ali McCann was set to join up with Northern Ireland for their double header against San Marino and Slovenia, although he was forced to withdraw from the squad due to injury.