Analysts had expected a profit of 5.26 billion roubles, a Reuters poll showed.
The bank said it expected a full-year 2018 net profit of no less than 24 billion roubles after reporting a net of 19 billion for 2017, also up 73 percent.
TCS Group's strong quarter stood out from Russia's wider banking sector which was shaken by the collapse of three of the country's biggest private banks in the second half of last year.
It also topped the 22 percent profit rise posted by Russia's largest lender, Sberbank.
"The group delivered another strong set of results... following accelerating growth of its core credit card business and the excellent performance of its new business lines," TCS said in a statement.
It announced a interim dividend payment of $0.31 per a share or GDR, with each GDR representing one share.
"Without a shadow of a doubt, 2017 was a watershed year," said Oliver Hughes, CEO of Tinkoff Bank, TCS Group's main business.