Mirza, who has returned to grass court Grand Slam after three years, and Mattek-Sands lost 4-6 3-6 to the Russian pair of Elena Vesnina and Veronika Kudermetova in one hour and 28 minutes.
It was expected that with a low combined ranking of 113, Bopanna (38) and left-handed Sharan's (75) entry would depend only on large scale withdrawals.
Nagal, India's second-highest ranked men's singles player, lost 2-6, 5-7, 3-6 to Berankis in a match that lasted two hours and six minutes at Court 17.
He said it is important for a player to remain focused. “Once the tournament starts, a player has to come out of the comfort zone before getting into the playing mood.’’