They both started wars in neighbouring countries, hold significant sway over energy markets, are known to brook no dissent and to covet spots in history. Russia’s embattled president, Vladimir Putin, and Saudi Arabia’s de facto ruler, Mohammed bin Salman, seem to have a lot in common.

Nearly eight months into Russia’s invasion of Ukraine, relations between Riyadh and Moscow are at a high point. As much of Europe, the US and the UK double down on attempts to combat an ever more menacing Russian leader, Prince Mohammed has instead chosen to deepen ties.

An Opec+ meeting in Vienna on Wednesday is the latest landmark in a growing relationship that is increasingly defying the demands of Riyadh’s allies and appearing to give Putin comfort at a critical juncture in the war. Both countries are likely to seek to raise oil prices by cutting global supply by 1-2m barrels a day.

Such a move would follow widespread disruption to gas supplies to Europe caused by the war and predictions of a worsening energy security crisis as the northern winter approaches. It would also alienate Washington, an ally that has tried to recruit Riyadh to the cause of decreasing supply pressures by opening valves to its enormous reservoirs.

Instead, Joe Biden finds himself staring down a partner in the Middle East whom he had personally visited during the summer as the extent of the supply crisis became apparent. Biden walked away empty-handed and, as a result, faces the uncomfortable prospect of taking high bowser prices to midterm elections. Perhaps more importantly for the US president, a rise in oil prices could be seen as helping fund Putin’s war effort.

“Previous Saudi administrations would have been much more sensitive to the US’s feelings and to messaging, even though they would likely do the same thing,” said Robin Mills, the chief executive of Qamar Energy. “Saudi has pretty much always done what it wanted in oil regardless of favours to the US but it usually sugar-coated it. Not this time.”

Another sign of a deepening bond between Moscow and Riyadh emerged last month when, in a rare moment of global diplomacy, Saudi diplomats secured the release of international prisoners, including five Britons, captured during fighting inside Ukraine. The optics were stark, and appeared sanctioned by Putin to give Riyadh a moment on a world stage; here were Saudi diplomats a long way from home brokering a deal that had nothing obvious to do with the Middle East.

“This was a gift from Putin to MBS,” said a British official familiar with the political dynamics. “Putin wanted it to happen, and he wanted it to seem as though the Saudis had achieved this through diplomacy.”

After four years of global fallout from the assassination of the Saudi dissident and journalist Jamal Khashoggi by Prince Mohammed’s security aides in Istanbul, the heir to the Saudi throne is in the midst of a global comeback. His attempts to position the kingdom as a regional power and global mover are among the 37-year-old’s core goals. Saudi officials have not condemned Putin’s invasion, and nor has Moscow weighed into Saudi Arabia’s invasion of Yemen over the past five years – a war that has left its neighbour impoverished and in ongoing need of significant aid.