Angelique Kerber felt her straight-sets win over Simona Halep at the WTA Finals reflected unfairly on the Romanian.
The world number one claimed a 6-4 6-2 victory in Singapore on Tuesday to make it two wins from two in the Red Group.
But Kerber said Halep, who won more return points than her opponent but converted just one of six break points, was closer than the score suggested.
"I think I was really playing good in the important moments and I was going forward when I had the chance," the German said.
"The match was really close and scores aren't like how the match was because it's always tough to play against Simona.
"She's a great player and she's always fighting until the last point so I was really trying to stay in the moment until the end."
Kerber broke twice in each set to take a giant step towards the semi-finals, with her last group match a meeting with Madison Keys.
The two-time grand-slam champion said her aggression paid off against Halep.
Kerber said: "I think the key was that I was positive the whole match and just serving good and being more aggressive in the important moments.
"[I was] just going for my shots, and of course bringing a lot of balls back. So that was my plan and I think it works well. So that was the key for the match against Simona today."