Northern Ireland's players celebrate winning 2-0 the UEFA Euro 2016 group F qualifying gootball match between Greece and Northern Ireland at the Karaiskaki stadium in Piraeus, near Athens, on October 14, 2014.AFP / Getty Images
Balkan rivalries cast a shadow over 2016 UEFA European Championship qualifying on Tuesday as the match between Serbia and Albania in Belgrade was abandoned after an Albanian flag considered provocative by Serbian fans was flown over the stadium by a drone.
English referee Martin Atkinson interrupted the match in the 41st minute, when Serbia defender Stefan Mitrovic managed to grab the banner and Albania players tried to protect it. Several Serbian fans invaded the pitch and clashed with Albania players.
"The Euro 2016 Qualifying match between Serbia and Albania has been abandoned and the circumstances will be reported to the UEFA Disciplinary Body," European soccer's ruling body said in a statement.
Albanian fans had been warned against attending the game between the two Balkan rivals that have had turbulent relations – mainly over the former ethnic Albanian-dominated Serbian province of Kosovo that declared independence in 2008.
Elsewhere, John O'Shea scored in his 100th international for Ireland in the fourth minute of stoppage time to give his side a dramatic 1-1 draw with World Cup holder Germany, which suffered another setback in Group D after losing 2-0 in Poland.
Cristiano Ronaldo also scored in the fourth minute of injury time to give Portugal a 1-0 win over Denmark and put his team's campaign back on track after a stunning 1-0 loss at home to Albania in Group I.
O'Shea cancelled out a goal from Toni Kroos in the 71st as Ireland joined Poland on top of Group D with seven points from three matches.
"Brilliant result, first and foremost. Okay, we had to live a little bit dangerously the last 10 or 15 minutes," O'Shea said. "Yeah, look, without a doubt, it's an absolutely fairy-tale ending, it was incredible, to get the 100th cap and score the goal to equalize against Germany, and hopefully to keep the momentum going to qualify for France."
Kroos hammered home a low drive in the 71st minute with what was then Germany's 17th shot. Ireland only had managed one until then, but O'Shea's late strike stunned Joachim Loew's team.
In Warsaw, Poland drew 2-2 with Scotland to remain top of Group D on goal difference over Ireland, while Georgia won 3-0 at Gibraltar. Poland and Ireland have seven points from three matches, while Germany and Scotland have four each.
Krzysztof Maczynski opened the scoring, but Scotland went up by one after goals from Shaun Maloney and Steven Naismith, only for Arkadiusz Milik to notch the final equalizer for Poland.
Northern Ireland continued to stun opponents in Group F, winning 2-0 in Greece for its third-straight victory to stay on course for its first ever European Championship qualification.
Jamie Ward got the early opener and Kyle Lafferty made it 2-0 at Karaskaki Stadium.
"We've sent out a massive statement tonight," said Lafferty, who has scored in all three matches.
New Greece coach Claudio Ranieri, who laughed off suggestions before the game that his job might be at risk, promised to shake up his side and "fight on" after his second home defeat left the 2004 European champions with just a point from three games.
In Helsinki, Romania's Bogdan Stancu struck twice in a 2-0 victory over Finland that moved his country into second place, while Hungary struggled in the Faroe Islands, winning only 1-0 with a goal from Adam Szalai.
In Group I, Ronaldo scored in a tense match in Copenhagen, heading home in the fourth minute of stoppage time following a cross from the right by Ricardo Quaresma.
Portugal made the better start in Copenhagen.
But the home team had the best chance of the first half when a shot by Denmark striker Michael Krohn-Dehli hit the post, after opportunities had fallen earlier for Nani and Ronaldo at the other end.
The tension remained high in the second half, with Nani and Ronaldo again testing Denmark keeper Kasper Schmeichel, while Portuguese goalie Rui Patricio saw off attempts by Krohn-Dehli and Nicklas Bendtner.
Switzerland earned its first points in Group E with a 4-0 win at San Marino.
Eintracht Frankfurt forward Haris Seferovic scored in the 10th and 24th minutes, Galatasaray midfielder Blerim Dzemaili added another on the half-hour mark, and Xherdan Shaqiri completed the scoring in the 79th.
Also, San Marino goalkeeper Aldo Simoncelli stopped a penalty from Ricardo Rodriguez in the final minute.
Switzerland moved level with Estonia and Slovenia with three points each in Group E, which England and Lithuania lead with six points each.
San Marino, ranked 208th by FIFA, remained last with zero points.
Switzerland, which reached the Round of 16 at the World Cup in Brazil, lost to England and Slovenia in its opening qualifiers.