India’s Achanta Sharath Kamal and G Sathiyan reached the pre-quarter-finals of the Qatar Open with impressive wins over seeded players on Thursday.

Sharath caused one of the biggest upsets of the tournament beating Japanese fifth seed Koki Niwa, 8-11, 11-9, 11-8, 14-12, 11-9 while Sathiyan had a roller-coaster match prevailing 6-11, 11-5, 2-11, 12-10, 10-12, 11-4, 11-8 over 15th seed Yuya Oshima.

Sharath, who does not have a good track record against Koki Nowa, was down in most games. But used his experience to finally get the better of the Japanese.

“I have never beaten him before, last year at the Asian Championships in the team event I had three match points and lost. In the first game I was ahead 8-5 and lost, in the second I was down 8-5 and won! The only way for me to beat him was to use my power, take some risks. In rallies, I had no chance against him. I also tried to slow down and not play fast,” he said after his big win.

Sharath will take on Jonathan Groth of Denmark next.

Sathiyan turned the match around when he held on to the fifth game 12-10 after deuce, after losing the previous game 10-12, to level score in the second consecutive thriller. But it gave him the necessary confidence as he won the last two games.

He attributed his success to the strong forehand top spin attack. “I am happy I pulled it off, particularly after losing the fifth game,” he said.

The path gets only tougher for him now, as he faces Japanese child prodigy Tomokazu Harimato in the next round.

The two Indians had earlier combined to enter the men’s doubles quarterfinals before bowing out 12-10, 10-12, 1-11, 10-12 to the top-seeded Chinese pair of Fang Bo and Lin Gaoyuan earlier in the afternoon. But before that they beat Sweden’s Kristian Karlsson and Mattias Karlsson, the fifth seeded pair, 11-6, 11-8, 8-11, 8-11, 11-4 in another thriller.