(Reuters) - As the buses carrying European finance ministers left for a gala dinner in the Latvian capital on Friday night, one of the party hung back at the hotel and then wandered off alone into the dusk.

Greece's Yanis Varoufakis had other dinner plans, he said, after a bruising first day of meetings in Riga that underlined his isolation as he tries to avert national bankruptcy.

While other ministers were feted by their entourages with food and warm clothing during the meeting in Riga, Varoufakis was seen alone at almost every turn, eschewing aides or any security detail.

"He is completely isolated," a senior eurozone official told Reuters on condition of anonymity. "He didn't even come to the dinner to represent his country," the official said of the event where ministers, serenaded by a Latvian choir, ate salmon and sea bass.

At breakfast before the meeting, Varoufakis and European Central Bank President Mario Draghi avoided eye contact as they picked up food at the buffet, Reuters reporters observed.

The hardening of the mood against Varoufakis risks deepening the divide that Greece must bridge with its creditors if Athens is to avert default.

After three months of largely fruitless negotiations, euro zone ministers warned him on Friday that the radical leftist Greek government will get no more aid until it agrees a complete economic reform plan, before the end of June.

Some countries are so frustrated by what they see as Greece's failure to compromise that one minister said it may be time to prepare for a Greek default.


Varoufakis, the only male minister at the meeting without a tie, said he was unfazed by the tone of Friday's meeting -- which Jeroen Dijsselbloem, the chairman of the euro zone finance ministers, described as "very critical" of Athens.

In a sign of the coolness creeping in, Dijsselbloem referred to Varoufakis as "the Greek colleague" to reporters in Riga, although he addresses him by his first name in meetings.

"I'm not surprised," Varoufakis told reporters. "When you are approaching the end of negotiations, the stance hardens."He denied reports that he had been insulted by ministers in Riga. "All these are false."

While his economic demands have fallen on deaf ears, Varoufakis has become an improbable heartthrob in Germany. ZDF public television lampooned its own news anchor for enthusiastically comparing the minister with Hollywood tough guy Bruce Willis, while Stern magazine published a gushing article on Varoufakis's "classical masculinity.”

But some ministers say they resent being lectured by an academic who has studied in Britain, taught in Australia and the United States and challenged the theoretical basis of European policymaking.

While Varoufakis criticizes the spending cuts demanded by international creditors, his euro zone peers insist only painful changes can lift Greece out of one of the deepest economic depressions in Europe since the 1950s.

According to people present in the room, several ministers rolled their eyes, closed their eyes or put their hands over their ears during Varoufakis' interventions at Friday's meeting.

"Eurogroup ministers don't like the fact that he is giving a small lecture when he is speaking to them," one euro zone official said. "And for that reason (chairman) Dijsselbloem stopped him yesterday, saying: 'Yanis, you don't tell us what we want to hear.'"

(Reporting by Robin Emmott, Ingrid Melander, Jan Strupczewski, Gederts Gelzis, Tom Korkemeier, Lefteris Papadimas; Editing by Ruth Pitchford)