Serbia's Euro 2016 qualifier against Albania was abandoned after a drone flown over the Partizan Stadium pitch carrying a pro-Albanian banner led to a clash between the two sets of players.

The Group I game erupted into controversy shortly before half-time in Belgrade when the drone, apparently flown in by remote control from fans outside the stadium, was brought down by a couple of Serbia players, with members of the Albania team attempting to intercept their national flag.

That prompted a melee involving numerous players and forced English referee Martin Atkinson to lead the players off the field, after some disruption off the pitch as well.

There were no signs of play being restarted more than half an hour after the suspension, with UEFA then confirming the match had been abandoned.

In the other Group I game, a headed goal in second-half injury time by Cristiano Ronaldo gave Portugal a much-needed 1-0 win over Denmark.

Ronaldo rose to meet Ricardo Quaresma's cross and bury his header past Kasper Schmeichel to claim all three points after referee Felix Byrch played five minutes stoppage time at the end of the game.

Denmark's best chance of the match came when Pierre Hojbjerg muscled his way through and fed Christian Eriksen, who teed up Michael Krohn-Dehli to fire in a shot that came back off the far post.

Ronaldo's goal lifts Portugal off the bottom of the table and into third in the five-team group on three points. Denmark remain second, level on four points with leaders Albania.

Meanwhile, in Group E, Haris Seferovic scored twice as Switzerland easily saw off San Marino. Blerim Dzemaili and Xherdan Shaqiri scored the other two goals.

In Group F, Hungary secured their first win of the qualifying campaign on, but made hard work of Group F minnows the Faroe Islands in a 1-0 win in Torshavn.

Adam Szalai netted the game's only goal in the 21st minute, the Hoffenheim striker left unmarked at the far post to turn home Roland Juhasz's cross after Frodi Benjaminsen had only half cleared a Balazs Dzsudzsak corner.

The 1-0 win lifted Pal Dardai's side on to four points from three games, with the pointless visitors remaining rock-bottom of the pool.

Bogdan Stancu was the hero for Romania, his two goals either side ensuring they beat Finland 2-0, for whom Alexander Ring was red-carded.