As celebratory gunfire was heard across liberated Syria, the diplomatic guns of Iran and Russia, in Doha to attend a major dialogue forum, fell silent, rendered powerless and irrelevant by events in Damascus.

Only 12 hours earlier the key external powers – Russia and Iran along with Turkey – had met five Arab states on the sidelines of the forum to issue a joint statement appealing for an end to military operations, preservation of Syria’s territorial integrity and consultations on a political solution between Bashar al-Assad’s regime and the opposition. It was a last attempt to retain a semblance of control over events, but the diplomats also anxiously discussed the fate of the Syrian president at the meeting, and whether there would be fighting on the streets of Damascus soon.

Russian representatives reported to the meeting that Assad was inflexible, refusing to accept reality or the necessity of dialogue with Turkey, the country sponsoring the military forces threatening the capital. Iran’s foreign minister, Abbas Araghchi looked pained and distracted.

Six hours after the weary diplomats left the meeting they woke to the news that Assad had fallen. Rarely have so many diplomats been rendered so irrelevant so quickly.

Earlier at the summit on Saturday, the Russian foreign minister, Sergei Lavrov, had been questioned onstage about Syria’s future, an increasingly uncomfortable encounter as he was asked to explain Russia’s role in the country over the past decade. At one point he was reduced by his interlocutor, James Bays from Al Jazeera, to blurting out: “If you want me to say: ‘yes we lost in Syria, we are so desperate,’ if this is what you need, let’s continue”.

Irritated, he badgered his interviewer to switch the discussion to Ukraine, familiar ground on which he could assert Russian military strength and American hypocrisy.

But he continued to hold the line that jihadist groups could not take hold in Syria, and Assad was the bulwark to prevent this. “It’s inadmissible to allow the terrorist groups to take control of the lands in violation of agreements which exist,” he said, a reference to insurgent group Hayat Tahrir al-Sham (HTS), which had led the breakout from Idlib province to Aleppo and then, extraordinarily, to Damascus.

Syrian rebels carry furniture from presidential palace after Assad flees the country – video

Syrian rebels carry furniture from presidential palace after Assad flees the country – video

He went through the ritual of referring to the need to implement UN security council resolution 2254 passed in December 2015, with a call for a democratic transition in Syria with which Assad had refused to engage.

Asked why Assad had not helped in the transition of power, Lavrov said: “No one’s perfect.” He made no reference to the 17 times Russia had vetoed UN security council resolutions in order to protect Assad.

As the interview continued, Lavrov fiddled uneasily when he was asked about the future of Russia’s naval base at Tartus and it airbase at Hmeimim, saying he was “not in the business of guessing” what would happen. All he knew was that Moscow was doing all it could to prevent “terrorists” from prevailing, adding that he was sorry for the Syrian people if they followed the fate of Libya and Iraq, two countries that suffered prolonged civil wars after strongmen were toppled by chaotic revolutions.

Asked if he truly thought Assad would win free and fair elections called for in resolution 2254, Lavrov changed the subject to the US presence in eastern Syria “supporting Kurdish separatists, including on the lands which historically belonged to Arab tribes, exploiting oil and food resources, selling them in the world market and financing the quasi-state they are building there”.

Lavrov is probably the most experienced diplomat on the globe, but never could he have been interviewed so self-evidently on the brink of humiliation.

Araghchi had also been doing the rounds in Doha, insisting it was possible for Assad to survive and clinging to the point that all external powers had agreed that Syria’s territorial integrity must be protected. But he had the haunted look of a man who knew events had suddenly run away from him. In previous days every effort to persuade Iraq, Tehran’s last bastion in the Arab world, to come to Assad’s rescue had failed. Iran’s 12-year engagement in Syria was coming to an end, marking the closure of its land corridor into Lebanon and Hezbollah. Iran’s whole security strategy of forward defence had collapsed, and now the government may need to rethink how it survives.

By contrast the Turkish foreign minister, Hakan Fidan, also a former head of Turkish intelligence, surrounded by a vast entourage, said little in public, sensing his country may be the biggest external beneficiary of Assad’s fall. Turkey has at its disposal the umbrella group of Syrian militias called the Syrian National Army and a relationship of sorts with HTS. But with power comes responsibility. More than any other country in the region it has the power to help Syrians form the independent consensus government their long struggle for liberation deserves.