Though she lost serve once in each set, the No.1-seeded Halep held all five of her other service games and went seven-for-seven on the return to totally dominate alternate Svitolina in 47 minutes, 61 61.
Halep finished it with a huge inside out forehand return Svitolina couldn't put back in the court.
"I'm really happy with how the match went," Halep said right afterwards in her on-court interview. "I served well and I played well today, and I'm really happy I could improve from yesterday's match."
Just like previous days, Halep was being urged on by a large contingent in the crowd from neighboring Romania - and the Romanian No.1, who already has five WTA titles this year, thanked them after.
"I want to thank all my supporters here tonight," she said. "You made this very special for me."
Halep was already in the semifinals but Thursday's win was the icing on the cake, as she is now 3-0 in Group Serdika, and 6-0 in sets. She is guaranteed to finish No.1 in the group, with No.2 coming down to Friday's match between Anastasia Pavlyuchenkova and Alizé Cornet - the winner of that one gets it.
Group Sredets is more complicated - the qualifiers will be determined by Friday's matches. All four of those players took the court earlier, with Ana Ivanovic beating Samantha Stosur in three sets (read more here) and Elena Vesnina beating Tsvetana Pironkova in three sets as well (read more here).
Halep may not know who she plays in the semis yet, but she knows what she has coming on Friday.
"I have a day off tomorrow so I just want to recover well and recover fast, and then I hope to play well on Saturday again," she said. "I will just try my best and enjoy this semifinal as much as I can."
Halep running the tables on her round robin group is exactly how Serena Williams ran the tables on her round robin group at the TEB BNP Paribas WTA Championships in Istanbul last week - Williams won all three of her round robin matches in straight sets in the first three days of the round robin portion, then had a day off on the Friday. Williams, who like Halep was the No.1 seed, went on to win the title.
There is one difference. Halep dropped 16 games in her three round robin matches - Williams, 15.