De Mistura said that he would report the outcome of the talks to the United Nations security council next week and would keep trying.
Bashar Ja'afari, the Syrian government's chief negotiator, criticized de Mistura's comments about Putin, saying it undermined the prospect of advancing peace talks.
Without pressure from president Bashar al-Assad's sponsors Russian Federation, or a great change on the battlefield, Assad felt no need to negotiate with an under-resourced, divided opposition.
He noted Thursday that no date has been set for a next round of the Geneva talks, and that said that under current circumstances "I don't think that another round would be quite effective".
In an unusual public appeal directly to a key powerbroker in the region, Staffan de Mistura told a TV interviewer the Russian leader should "convince the (Syrian) government that there is no time to lose" in efforts to reach peace in Syria after more than 6 1/2 years of war. He described Syrian government envoys as unwilling to meet opposition representatives face-to-face, which forced all communication from both sides to take place in separate meetings with United Nations officials.
The Damascus government uses the term to refer to all armed opposition against President Bashar Assad.
His statement came at the end of the eighth round of indirect talks in Geneva between delegations representing Damascus and the opposition in Syria's brutal, almost seven-year war.More news: Facebook is adding the ideal feature for those annoying 'Facebook friends'
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In a rare admission of failure, de Mistura also said he needs to come up with "new ideas" for future talks.
The eighth and latest round of peace talks ended in Geneva with little more than hope for a new round in January.
In a statement issued by a revamped opposition delegation team in Riyadh, Ja'afari said he would not negotiate under blackmail, ahead of the talks demanded in a political transition in which Assad did not participate.
Asked on Swiss broadcaster RTS what signal Putin could provide now, de Mistura alluded to how territorial gains would be "temporary".
Russian President Vladimir Putin during a surprise visit on Monday to Russia's Hmeymim air base in Syria, declared that the work of Russian forces was largely done in backing the Assad government against militants, following the defeat of "the most battle-hardened group of global terrorists".
The Syrian political situation has been deteriorating since the protests emerged with the Arab Spring revolutions in 2011, when the opposition created the Free Syrian Army to face Assad's forces.
De Mistura also said it was "regrettable" Assad's delegation had refused to meet face-to-face with the opposition in what have been indirect talks in Geneva.