Karrueche Tran knows how to pick her battles and her rival Rihanna isn't one of them. 

Chris Brown's on-and-off girlfriend showed up to Greystone Manor nightclub in Los Angeles on Sunday, but when she learned that Rihanna was there, she left before she could party. 

According to a source close to Rihanna, Tran did the right thing by leaving before any trouble could start. 

"Rihanna wasn't about trouble or drama and homegirl knew that and did the best thing she could for her and her friends - and that was to bounce, immediately!" the source said. 

"Everybody in town knows Rihanna helped put Greystone on the map, that's her home away from home," the source added. "She's royalty there. No disrespect but other bi**hes need to know their place and all will be well, as evidenced by last night."

Rihanna, who was previously rumored to be pregnant appeared to have shut down those reports as sources said she was indeed drinking at the club.

"Of course she was [drinking]," the source said. "What else would you do in a club?

Meanwhile, it appears as if Rihanna and Drake are officially an item. Enstars reported last week that the Toronto-born rapper recently released a new song entitled Days In The East which is rumored to be inspired by Rihanna. 

Some of the lyrics include: 

"Told you about giving him chances on chances on chances/ He's not holding you down, he's holding you back right now."

Tags: Rihanna Karrueche Tran Drake Chris Brown