* Putin stands ground on Syria, wins plaudits at home
* Russian seemed to relish his isolation at summit
* Back to square one for Obama who trumpeted Russia "reset"
At the end of a tense two-hour meeting with Russian President Vladimir Putin, Barack Obama - slumped over and serious - tried to lighten the mood with a joke about their favourite sports.
"And finally, we compared notes on President Putin's expertise in judo and my declining skills in basketball," the U.S. president told reporters at the G8 summit, after the two men gave formal statements emphasising their common ground rather than their sharp differences on how to end the Syrian crisis.
"And we both agreed that as you get older it takes more time to recover," Obama said.
Putin - who folded his hands and glowered through most of the exchange - was having none of it. He waited for the audience to finish laughing, smiled icily and stuck in his spear.
"The president wants to put me at ease with his statement about how he is growing weaker," retorted Putin.
Few expected any diplomatic breakthroughs from the meeting in Northern Ireland, less than a week after Obama's administration announced it would provide military support to rebels fighting Moscow's ally, Syrian President Bashar al-Assad.
But Putin - who scowled, lectured and fidgeted while resisting the forced bonhomie of the two-day summit with the leaders of world's richest nations - seemed positively to relish his isolation.
It was a vintage display of Putin's world view forged since the Soviet Union's fall in 1991: the United States will inevitably overreach, and Moscow must always step forward to demonstrate the limits of U.S. power.
The point-scoring continued after Obama left for the next stop on his European tour to deliver a speech in Berlin, where he called on Russia to agree nuclear weapons cuts. Moscow responded that it "cannot take such proposals seriously" while the United States is pursuing anti-missile defences.
Putin's performance at the summit won the former KGB spy plaudits at home, where he is trying to reassert his authority after protests and in the face of a stuttering economy.
"I think he got all the bonuses domestically. He held his head high, stood tall and did what he pledged to do - to be very firm but not confrontational," said Dmitry Trenin, a political analysts at the Carnegie Moscow Center think tank.
U.S. officials played down the rebuff over Syria, describing the Putin-Obama meeting as "businesslike" and emphasising the common ground over a sectarian civil war in which the two presidents are now both committed to arming the opposing sides.
"We both want to see an end to the conflict. We both want to see stability. We don't want to see extremists gain a foothold," said White House Deputy National Security Adviser Ben Rhodes.
"I think both leaders went out of their way to underscore that they can work together on this issue," Rhodes said. "If they can project a message that they have a convergence of views as it relates to a political negotiation, that keeps the possibility, the prospect of that political track alive."
But even their one joint initiative faced a setback. One source at the summit confirmed that Syrian peace talks called last month by Moscow and Washington, initially meant to be held in June, then July - were now postponed until August at least.
The tense exchange between Putin and Obama marks full circle since the administration of the newly elected Obama called for a "reset" in ties with Russia in 2009 after a row between the Cold War foes over Russia's 2008 war against U.S.-ally Georgia.
Obama has touted the Russia reset - in which his then Secretary of State Hillary Clinton presented her Russian counterpart with a big red "reset" button - as one of his signature foreign achievements. (Clinton's aides notoriously mistranslated the button and labelled it "overload" in Russian.)
WE ARE GOING TO DELIVER
Putin arrived the night before the summit and made his unrelenting position clear at a pre-summit press conference with his host, Britain's David Cameron.
Putin hammered home his point that arming Syrian rebels was reckless by zeroing in on an incident from last month in which a rebel fighter was filmed biting on the entrails of an enemy.
"One does not really need to support people who not only kill their enemies but open up their bodies, eat their intestines in front of the camera," he said as Cameron stood by.
From the outset, Putin was isolated at the summit.
Canadian Prime Minister Stephen Harper accused Putin of supporting "thugs" and said Syria would be discussed by the other seven powers, with Russia as a "plus one". Putin's foreign policy adviser Yuri Ushakov fired back, saying the Canadian's remarks came "from the position of an outside observer".
After the bilateral meeting with Obama, Putin went to a dinner in a lodge on the shore of Lough Erne where the leaders discussed Syria over a dinner of crab, fillet of beef, and whisky-laced custard.
Putin refused to accept any public declaration that could imply Assad would go. He won: the final communique on Syria did not even mention Assad's name.
He also defended Russia's arms shipments to Syria and suggested that more might be coming: "We are supplying weapons under legal contracts to the legal government. That is the government of President Assad. And if we are going to sign such contracts, we are going to deliver," he said.
Western officials still suggest that Moscow's alliance with Assad is not as strong as Putin's remarks imply. "Clearly Putin doesn't hold back with his views," said one Western official who tried to play down the disagreements.
"Don't expect Vladimir Putin to pick up the phone to Damascus and say 'the game's over'," he said. "The Russians have deliberately and utterly not tied themselves to (Assad) as an individual and have always given themselves some wriggle room."
But Western officials have suggested for months that Moscow might soon drop Assad, only to find Putin as staunch as ever, even when the war was going the rebels' way. Now, with Assad's forces having seized battlefield momentum in recent months, there seems less reason than ever for Moscow to ditch him.
On Wednesday, the Kremlin followed up the Syria dispute by pouring scorn on Obama's proposal for nuclear cuts. Russia says it cannot give up missiles while Washington is working on anti-missile defences that could defeat a smaller Russian arsenal.
"How can we take the idea of strategic nuclear weapons reductions seriously when the United States is building up its ability to intercept these strategic nuclear weapons?" Deputy Prime Minister Dmitry Rogozin said. "These things clearly do not go together. It's obvious that Russia's highest political leadership cannot take such proposals seriously."
Putin has another reason to want to look tough abroad, to consolidate support at home at a time when the faltering economy is hurting his standing.
"Despite the emotions, the summit was in many respects a success for Russian diplomacy," the business daily Vedomosti wrote, suggesting Russia had made no concessions and the West had shown it was not ready to act if Moscow was not on board.
Moskovsky Komsomolets, a popular daily with a reputation for catching the public mood, was more uneasy: "Putin is alone again," it wrote. "But do we need to be sorry about it?"