Somdev, ranked 96, recorded a 6-2 7-5 win over his 483-ranked compatriot in his opening round in one hour and 28 minutes at the centre court of the R K Khanna tennis stadium.
Myneni, who recently made his Davis Cup debut, bowed out after a gruelling first round contest against Italian Thomas Fabbiano. The Indian wild card lost 6-7 (4) 6-7 (4) after one hour and 59 minutes of intense tennis.
Karunuday, playing only his second main draw at a Challenger event, began well by serving out the first game at love with an ace but keeping the points short was a big task against Somdev, who has an amazing ability to retrieve the ball.
Kaurunuday kept playing aggressively with big shots, a strategy which has worked against Somdev for a few players. There was the risk of committing errors with that ploy and it happened.
Karun was again down by a breakpoint when he hit a forehand long but saved it with good service. Good rallies followed in the next game and it was now Somdev, who was down by three breakpoints. In all, Somdev saved four chances in the sixth game to keep the lead with him.