Caroline Wozniacki and Simona Halep cruised into the quarter-finals at the Qatar Open on Thursday, while defending champion Karolina Pliskova was knocked out by qualifier Catherine Bellis.
Wozniacki, the Australian Open champion, was playing Angelique Kerber of Germany in the quarterfinals.
Wozniacki, last year's finalist from Denmark, came into the matchup having lost her last three hardcourt meetings against No. 16 seed Kvitova but coming off a hot run that had seen her notch 12 semifinal victories in a row.
Her protests fell on deaf ears as the umpire refused to take action.
The Romanian raced to a 5-1 lead in the first set before Makarova, the world number 36, showed some defiance by breaking Halep's serve and threatening a comeback.
'She'll hit the ball and then two seconds later when the ball is on my side and I'm right about to hit, she'll start grunting and make a loud noise.
'Obviously she's a player that tried to get into your head, ' Wozniacki added in her post-match press conference. And she'll change the grunt according to what she feels like.
Asked if she thought her opponent was grunting deliberately, Wozniacki responded: "I think that she didn't do it in the second set, so..." "It's in the rules that they're not supposed to do that". "But you know, on the other hand, I'm very proud of myself that I won it".
"It was a tough match. She used unfair methods, but it is what it is", she told afterward.
Niculescu wasn't prepared to take the cheating accusations lying down, allegedly firing back when she spoke to the media.
"She has a hard game to play against when she's on, but as well when she isn't, because you don't get any rhythm and you know that eventually she's going to start hitting those balls in and you need to be ready for it, " she said. "I didn't have much time to recover before this tournament, but today was too much, and I chose to stop". The rout was finally broken with the American youngster firing a bullet-like forehand return victor to get on board, regaining her confidence in the process.
"I'm really glad that I could finish it in two sets and play like I played", said Halep.