That's why I suggest getting the big card from the get go. When you open the account, the requirements are lower as you have the bait of new account opening.
I've not been able to upgrade to Infinia despite constant requests to my RM. Part of which is his laziness as well, but it's not an easy card to get. From what I've heard, you either need to be high net worth with a lot of money invested in HDFC, or need to be 45L+ annual salaried. And even that needs to be regular salary, bonus at end of year may not count depending on your luck (unfortunately it didn't in mine).
Diners club black is much easier to get. 1.75 lakhs per month income(pre tax) or 21 lakhs ITR either will do easily. But now the reward cap is much lower and Infinia seems much better. Though for now diners isn't allowed to take more customers in India due to RBI data storage policies.