Yuki and Ramkumar's early exit from SW19 qualifiers latest in a disappointing year for singles players from India.
Ranked 170, Ramkumar came into the tournament after winning both his singles in the Davis Cup tie against Denmark.
Ramkumar Ramanathan today improved his career-best rank to 168 in singles, while Sania Mirza was unchanged at number seven in the doubles.
Davis Cup: Ramkumar Ramnathan wins but Prajnesh Gunneswaran bites dust, India win 4-1 against Uzbekistan
Ramkumar Ramnathan continued India's domination of the home tie by outclassing Sanjar Fayziev 6-3 6-2 in just 67 minutes.