Tyga's new video "Stimulated," featuring Kylie Jenner, is doing the rounds, but “Keeping Up With the Kardashians” star Kim Kardashian thinks the chemistry between her younger sister and the rapper was just “mediocre.”

The new song released Sunday and shows the couple getting close, but Kardashian reportedly feels that “Bound 2,” featuring both her and her husband Kanye West, was better, Hollywood Life reported, citing an insider.

“Kim saw Kylie and Tyga’s "Stimulated" music video and she wasn’t impressed. She thought the song was just OK and felt the chemistry between Tyga and Kylie was mediocre,” the insider told Hollywood Life, adding: “Kylie‘s attempting to steal Kim‘s swag and she’s failing." The report also said that it seemed like Kardashian was jealous of Jenner after the new video by the "Rack City" rapper.

“Kim told Jenner that Bound 2 was ‘epic and fabulous in all proportion’ and said ‘the chemistry and sex appeal that my husband and I exuded can’t be duplicated.’ She reminded Kylie of how big "Bound 2" was. It was the most talked about music video for months and celebrities were imitating her and Kanye’s video,” the insider said, adding: “She went further with Kylie, explaining to her baby sister that she’s the original video vixen of the family and the reigning queen of television and social media too!”

Jenner and Tyga have reportedly been dating for months, but made the relationship public only last month after Jenner turned 18. The latest video showed the two kissing and reports also said that Tyga’s former lady-love, Blac Chyna, was not very happy seeing the video.

“[Blac] thought Tyga and Kylie’s kissing scenes looked ‘amateurish’ at best,” a source had reportedly told Hollywood Life after the video released, adding: “It’s obvious that Kylie could use some kissing lessons from Blac Chyna. And if her awkward kissing is any indication of her skills in the bedroom, Kylie needs some more practice.”

“Stimulated” has already garnered over six million views, while “Bound 2,” which was released in 2013, has over 50 million views so far.