Mobilisation of voters, and the role of election monitors, played a big role in the opposition victory in both countries.Last weekend, the DE civic action group in Hungary sent 70 election monitors to Serbia, to work with students' movement representatives, visiting polling stations in the northern Serbian province of Vojvodina. During the summer, even before the election was called, they held workshops to share their experience and methods from the Hungarian election with the Serbian students.

A key technique was to identify "infected" polling districts in advance - places where the surprisingly high number of votes for the governing party at previous elections suggested that voter intimidation or "chain voting" techniques were used."From around 16:00 on election day, we noticed groups of masked hooligans - Vučiċ supporters - gathering near voting stations," Péter Klemm, a student activist from Subotica, told the BBC. "So we sent mobile teams, and started filming everything." Combined with the "stationary" monitors already in place, 20 to 30 volunteers at each threatened polling station acted as a strong deterrent, he believes, and prevented intimidation or fraud.Orbán in Hungary, Vučiċ in Serbia, both looked invincible. Both were powerful leaders, in office for 16 and 14 years, who had taken over state institutions and established business empires overlapping the two countries.Orban chose cheese, Vučiċ meat, when they sat down to a quick lunch of traditional burek pastries at a small, popular town centre bakery in Subotica almost a year ago.They continued to a local winery, to talk about oil and other business deals - the planned Hungarian purchase of Serbia's Nis oil refinery.

The two nationalist leaders found much in common, in business and politics, not least their friendship with Vladimir Putin in Russia and Chinese President Xi Jinping, and their strong support for Milorad Dodik, the separatist leader of the Bosnian Serbs. A high-speed railway between Belgrade and Budapest is being built with Chinese finance and know-how.The parallels between the fall from power of the two men are extraordinary.

Aleksandar Vučiċ admitted defeat at exactly 21:30 on Sunday evening, just as Viktor Orbán did on 12 April. Few observers expected either leader to concede peacefully.There has been speculation this week that Vučiċ spoke to Orbán twice on Sunday night to ask his advice - once before he conceded, and again at 23:15.

And that Orbán convinced his Serbian ally not to use force. Vučiċ denies that he spoke to Orbán before he made his announcement, but acknowledges the later conversation.

Viktor Orbán, contacted by the BBC, declined to comment. An hour before polls closed in Serbia, masked and hooded vigilantes took up position in central Belgrade.

During voting, similar groups were photographed at many polling stations, and blocked by election monitors.There is another strange numerical similarity. The Student List will have 140 seats in the 250-seat Serbian parliament, the same number Péter Magyar's Tisza party won in the 199-seat Hungarian parliament.Magyar was the only European leader to ring the students directly to congratulate them that evening - and probably the only one who had their number."It is always good to hear that the story of Tisza could provide an inspiration for other nations," the Hungarian prime minister told the BBC."The result of the Hungarian election clearly showed us that what we are doing here is right," the head of the Student List, Ilija Srdanoviċ, said on the eve of the vote.Srdanoviċ was one of those Péter Magyar spoke to that Sunday evening.