GENEVA (REUTERS) - The deal between the United States and Russia on Syrian chemical weapons was due in no small part to the labours of foreign policy veterans with contrasting styles: Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov.
While their bosses, presidents Barack Obama and Vladimir Putin, get on poorly and can stoop to point scoring, the two ministers have what diplomats like to call "a good working relationship".
"We've had our differences here and there on certain issues," Mr Kerry said of recent tensions that have brought US-Russian ties to some of their lowest points since the Cold War.
Throughout it all, "Sergei Lavrov and I have never stopped talking," Mr Kerry told a news conference on Saturday when he announced the Syria agreement after nearly three days of round-the-clock negotiations.
The pair have helped keep the US-Russia relationship from hitting even worse lows as Moscow and Washington argued not only over Syria but also about American fugitive spy contractor Edward Snowden and human rights in Russia, US officials say.
Just 10 days ago, Mr Putin publicly called Mr Kerry a liar for suggesting that Syrian rebels were not dominated by radical Islamists.
To smooth things over, Mr Lavrov apologised - or at least explained - to Mr Kerry in a phone call, a senior State Department official said. The Kremlin got a bad translation of the secretary of state's remarks, Mr Lavrov told Mr Kerry.
The Geneva accord to take away Syria's chemical arsenal leaves major questions unanswered, including how to carry it out in the midst of civil war and at what point the United States might make good on a threat to attack Syria if it thinks President Bashar al-Assad is reneging.
But it was a rare common effort between Moscow and Washington and the product of the most significant direct US-Russia diplomacy on a global crisis in years.
The Syria agreement "shows how important it is for us to go beyond those things ... some people try to make them as obstacles in our relations, some suspicions or concerns that are created artificially," Mr Lavrov said on Saturday when asked whether the United States and Russia might again try to "reset" their relations.
After the Russian wound up his long-winded answer, Mr Kerry, a former US senator, teased him: "I was just thinking Sergei, you could be a senator."
Mr Lavrov and Mr Kerry might be diplomatic partners and able to rib one another in public, but they are cut from different cloth.
The Russian foreign minister has an often-dour public visage and can be prickly and sharp-tongued. Those who have negotiated with him say he has a razor-sharp mind, honed over four decades of diplomatic service since his 1972 graduation from the then-Soviet Foreign Ministry's international relations institute.
By contrast, Mr Kerry is a former politician and presidential candidate with a deep belief in personal diplomacy and his own powers of persuasion.
Mr Lavrov does not wander off message; Mr Kerry's former independence as a senator shows in the occasional remark that goes beyond the White House script.
While their relationship helped the Syria talks, ultimately foreign policy is dominated in Moscow by Mr Putin, and to a lesser extent by the White House in Washington.
The Syria chemical weapons plan, first put forward last week by Mr Lavrov, would not have been announced without Mr Putin's approval.
"The Russian foreign minister does not have an independent political identity in the way that senators-turned-secretaries of state like (Hillary) Clinton or Kerry do," said Matthew Rojansky of the Woodrow Wilson International Center for Scholars.
"This is a strong system and Putin is very much in control and Lavrov serves that system," said Mr Rojansky, director of the center's Kennan Institute.
Mr Lavrov left the Intercontinental Hotel talks venue twice on Friday to field calls from Mr Putin he took at Russia's mission to UN organisations in Geneva.
The Intercontinental was where Mr Kerry's predecessor Clinton gave Mr Lavrov a peace offering in March 2009 in the form of a box with a large red "reset" button.
The reset in US-Russia ties did not last long, foundering over disputes on Iran, Syria and Snowden.
Mr Lavrov, Russia's top diplomat since 2004, appears to get on better with Mr Kerry than he did with either Mrs Clinton or former Secretary of State Condoleezza Rice.
Dimitri Simes, president of the Washington-based Center for the National Interest think tank, said he last saw Mr Lavrov in July.
"It was quite clear that Lavrov was concerned about the status of the US-Russian relationship, was not happy with the US position on Syria. But my impression was that he felt that he had a good working relationship with Secretary Kerry."
Mr Kerry and Mr Lavrov have spoken by phone 11 times since the Aug 21 gas attack outside Damascus that sparked US threats to use force, according to a State Department tally.
Their struggle with the Syria issue began in early May, when Mr Kerry travelled to Moscow, met with Mr Putin and pressed the Russians to become more involved in efforts to end Syria's civil war, which has killed more than 100,000 people.
"Just work with Lavrov on it," Mr Putin said near the end of the more than hour-long meeting, according to the State Department official.
The two ministers took a long walk - a favourite Kerry tactic - then huddled with a small group of advisers in a backroom, where they drew up an announcement for a meeting in Geneva aimed at a political transition in Syria. But that conference has yet to be held.
After a midnight news conference to announce the peace conference plan, they had dinner. Mr Lavrov brought out a bottle of wine from the late 1940s, the senior official said.
"They talked about hockey. They both love sports," the official said. "Lavrov loves soccer. Kerry played soccer."
Mr Kerry's personal diplomacy with Mr Lavrov continued in Geneva this week, with a dinner of salad and fish on Thursday night that included only one aide each, and a ride in his limousine on Friday morning en route to the UN's Geneva headquarters.
Those personal touches helped move the talks towards agreement and avert a US military strike on Syria.