The 37-year-old scored just before halftime, putting Babina Noko ahead, but Arrows mounted a strong second-half comeback to win 3-1 at King Goodwill Zwelithini Stadium.
While Grobler's performance earned him the fan-voted Man of the Match award, which comes with a R100,000 prize, he insisted he did not deserve the recognition.
"I'm an honest person, I'm shocked. I don't think I had a great game. I should have scored more goals," Grobler admitted as quoted by FarPost.
"We have a great group of players, but we have to understand we need to be better than we were. In the first half we were very good, but in the second half we didn't come out with the same intensity. We only have ourselves to blame, and the international break didn't help."
Grobler also addressed controversy over his goal, which appeared to involve his hand and says he also has to look at the game to see how he played.
"The goal, look, I have to go and look at it. I don't know where it came off because I just dived at the ball, so I can't tell you where it actually hit me, but it went in," he said.
"I have to look at myself as well. I thought I was not where I should be. In the first half, I could have had three goals."
Grobler and his Babina Noko teammates will now turn their attention back to the league, aiming to bounce back after a disappointing knockout exit and build momentum for the remainder of the season after the international break.
Golden Arrows will look to break their scoring drought when they host Stellenbosch FC, while newly promoted Milford FC aim to continue their impressive league start when they face Polokwane City in Wednesday's Betway Premiership action.
Richards Bay head coach Ronnie Gabriel says his side are gunning for their first win of the new Betway Premiership season against Kaizer Chiefs at home on Wednesday.
Aubrey Modiba says Mamelodi Sundowns must bounce back from their MTN8 semi-final first leg loss to Golden Arrows with victory over AmaZulu in the Betway Premiership on Tuesday.
Orlando Pirates coach Abdeslam Ouaddou has challenged Sebastian Pedersen to raise his fitness levels after getting his first glimpse of the Norwegian striker in competitive action.
