If Russia has recently regarded Turkey warily as a result of Turkey's successful backing of Azerbaijan in its recent war with Armenia over Nagorno Karabakh, being on opposite sides in Syria and Libya, Turkey's supply of arms to Ukraine, and Turkey's refusal to recognize Russia's annexation of Crimea, in the run up to the Putin-Erdogan summit in Sochi on September 29, 2021 and in its aftermath, the music changed. Professor Alexander Dugin, a Putin advisor and a leading light of the Eurasian school attached historical significance to the meeting: “At this summit, the heads of the two states drew their red lines and a roadmap for the new world. From now on, Turkey and Russia have embarked on a new path, and this will affect both regional dynamics and the whole world. " The pro-Kremlin television commentator and presenter Dmitry Kiselyov pronounced that Erdogan and Putin had achieved unity on almost all issues. During the summit Putin emphasized the quest for compromises, but Russian commentators believe that Erdogan generally acceded to Putin, and drew encouragement from a Turkish military withdrawal from Idlib in Syria. In seeking to explain the more accommodating policy of Erdogan, Russian commentators concentrated on Turkey's economic and political vulnerability. The latter was the result of a chill between Erdogan and the Biden administration that deprived Erdogan of the option to play both sides.
A survey of Russian comments surrounding the Erdogan-Putin summit follows below:
Putin and Erdogan (Source: Kommersant.ru)
Turkey's Economic Vulnerability
Writing in Ura.ru, Ekaterina Lazareva believed that the economy was Turkey's Achilles heel and Putin was well aware of this vulnerability: " If Erdogan pursues the policy of expanding the Turkish presence in Idlib (Syria) and continues to meddle in affairs of Transcaucasia region, Russia will strike the weakest element - the Turkish economy."  According to Lazareva's analysis, Putin twisted the knife by accentuating the positive in bilateral economic relations but simultaneously driving home Turkey's dependence upon Russia. He spoke of growing trade turnover and the millions of Russian tourists visiting Turkey. Putin also pointed out to his guest that Russian investment in Turkey dwarfs Turkey's investment in Russia. Erdogan was also reminded by Putin of Russia's help in terms of Turkey's energy requirements ranging from the Turkish Stream gas pipeline to nuclear power plants.
Nikita Danyuk Deputy Director of the Strategic Studies and Forecasts Institute at Moscow's Peoples Friendship University warned Turkey that if it succumbed to its "expansionist aspirations" it could expect economic blowback from Russia: If the contradictions won't be resolved soon, there is a chance that some economic projects could be curbed; and tourism and imports of agricultural products will suffer as well." Danyuk recalled that when relations soured previously, Russia banned Turkish agricultural imports on the grounds that it had found pests in Turkish produce. Pavel Feldman, Deputy Head of the Philosophy and Political Science Department at the Academy of Labor and Social Relations (ALSR) claimed that Putin had shown Erdogan that " it's not worth putting trade with Russia at risk by making aggressive statements towards us."
Nikita Danyuk (Source: Regnum.ru)
Other Russian outlets have highlighted Turkey's economic vulnerability. The EADaily news agency headlined the day after the summit: The Turkish Lira Is Falling, Inflation Is Skyrocketing. Erdogan Risks Losing the Sympathies of Turkish Voters." The commentary reported that Erdogan was floundering in the public opinion polls due to annual inflation approaching 20%, growing unemployment, the weakening of the Turkish Lira, and a drop in foreign investment.
Interfax reported that "prices for food and soft drinks in the country increased by 28.79%, energy prices rose by 22.77%, transport services - by 20.21%, and utilities - by 20.97%."
One accelerant of inflation was energy prices triggered by global gas shortages, and this affected Turkey as well. 
Kiselyov remarked on Turkey's good fortune in having Russia as a friend under these circumstances:
"The Blue Stream gas pipeline runs between Russia and Turkey. The new "Turkish Stream" started operating at full capacity, through which gas went to Hungary and Croatia. And this is how far-sighted the decisions of Putin and Erdogan, made during the visit of the Russian President to Turkey at the end of 2016, when they agreed on the Turkish Stream, turned out to be. Against the background of the gas hysteria of the European Union, Turkey now feels very confident. Add to this the construction by Russia of the first nuclear power plant in Turkey - the Akkuyu project."
Turkey's Political Problems
In addition to Turkey's economic vulnerability commentators stressed Turkey's diplomatic problems and particularly the chill in relations with the United States.
Prior to the summit, the nationalist Duma member Vladimir Zhirinovsky leader of the Liberal Democratic Party advised the Russian authorities to highlight Turkey's weaknesses starting with the restless Kurdish minority: ""The weakest point is the Kurds, there are 40 million of them. They expect help from any country and they will gladly receive weapons - more than they have now, the most modern." Turkey should watch out for French intervention on behalf of Armenia. Additionally, the Balkan countries and Greece nourished historical resentments against Turkey and "they know what it is to live five centuries under the Turkish yoke."
Turkey's main diplomatic problem was its relations with Washington. Military expert Alexei Leonkov believes that Turkey cannot hope to receive the weapons that it wants from the US particularly if it does not intend to play by America's rules: "There remain quite a few disagreements between the United States and Turkey, especially over Syria and Iraq. In this regard, I do not expect the United States to supply the equipment that Erdogan wants. And this, in turn, means that while cooperation will continue, it will be at a level that is unlikely to suit the Turkish side."  Turkey's refusal to forego the purchase of the Russian S-400 air defense systems led the US to exclude Turkey from receiving the F-35 planes and according to Putin's press secretary Dmitry Peskov, this issue was discussed at the summit along with suggestions of intensified cooperation in the field of aviation. 
Putin's willingness to meet Erdogan immediately after emerging from Covid isolation contrasted with the nebulous scheduling of a meeting with Biden perhaps at the G20 summit in Rome. Erdogan called the US National Security Council Coordinator for the Middle East and North Africa Brett McGurk a "terrorists' mastermind." McGurk was according to Erdogan an enabler of the Kurdish PKK
Middle East expert Stanislav Tarasov claims that Erdogan's position vis a vis Russia has weakened because Turkey now lacked American backing: "When Erdogan made any statement, Moscow knew that the Americans are also behind it. However, this time, Biden gave up these tricks and left Erdogan one-on-one with Putin." One result was the withdrawal of Turkish forces from Idlib." "I'm talking about several thousand soldiers and many armored vehicles," noted Tarasov.
The President of the Middle East Institute, Evgeny Satanovsky, who has been a critic of the attempt to court Turkey, also took note of the Turkish withdrawal gave his grudging admiration to Putin's policy: "Putin is able to maintain relations with Turkey instead of fighting with it in some big regional war." Satanovsky was even willing to see the silver lining in Turkey's continued presence in Syria: "As long as Turkey's presence in Idlib remains bothersome for Assad, he cannot sell his allegiance to the Americans or the Europeans, as Arab leaders usually did when they stopped needing us."
 Inosim.ru, October 3, 2021.
 Vesti.ru, October 3, 2021.
 Ura.ru, September 29, 2021.
 Ura.ru, September 29, 2021.
 Eadaily.com/ru, September 30, 2021.
 Interfax.ru, October 4, 2021.
 Lenta.ru, October 4, 2021.
 Vest.ru, October 3, 2021.
 Vesti.ru, September 26, 2021.
 Russian.rt.com, October 3, 2021.
 Ria.ru, September 30, 2021.
 Vz.ru, September 30, 2021.