In her previous match too, Saina had to put up a tough fight against the local Brazilian girl, who ranked 72 in the world rankings.
Saina got off to a winning start in Rio but faced unexpectedly tough opposition from unheralded Brazilian opponent Vicente Lohaynny.
The London Olympic bronze medallist said that Lohaynny "surprised her".
"First round is always tricky and difficult to play. Definitely I was taken for a surprise. The crowd was cheering her a lot also so she had the (home) advantage. It was a confidence boost for her. It was not the best or worst match but I am happy with the way I played. The draw is very tough, I just want to take one match at a time," Saina said after her 21-17, 21-17 win in 39 minutes.
Prior to her loss, the largest Indian badminton contingent at the Olympics had already seen two of its medal hopes dashed out early in the group stages itself when the combinations of Ashwini Ponnappa-Jwala Gutta and Manu Attri-Sumeeth Reddy crashed out.
Here's how twitter reacted to her unexpected loss: