Patel removed Brendon McCullum for three as New Zealand limped to lunch in complete disarray at 61-6 with five wickets falling to catches behind.
"There was just enough in the wicket to suggest it was difficult and they swung the ball as well," Vettori said.
"If we look through the dismissals there weren't too many we were disappointed with. A couple of things didn't quite go our way."
Vettori and Ryder held Indian bowlers at bay for three hours.
Vettori, the more aggressive of the two, raced to his hundred off 139 balls and smacked 14 fours and two sixes before he departed after tea, also edging behind.
Ryder, who had been more circumspect, was on 77 when Vettori was dismissed and raised the tempo as he closed in on a first test ton.
