For example, in Moscow they will not really shed a tear if the Iranian oil sector encounters difficulties following one Israeli action or another.

About 90% of Iran's oil exports (about 1.6 million barrels per day) currently go to China, and at a discounted price. 

Exports from Iran are at the expense of exports from Russia. 

During the first seven months of the year, Russian oil exports to China fell by about 22% - a worrying trend for Moscow. If the supply from Iran runs into one or another crisis, this opens the door for Russia (but also for other countries) to increase sales to China.