L.A. Sparks rookie Jantel Lavender -- the #5 overall pick in the 2011 WNBA Draft -- allegedly kneed her ex-BF in the junk so hard, his groin area was "throbbing from the pain" ... this according to legal docs obtained by TMZ.

According to court papers filed in L.A. County Superior Court, Lavender's ex Adam Ashley obtained a temporary restraining order against the 6'4" athlete two weeks ago ... claiming he's been "in hiding" ever since a July 5 altercation where Lavender allegedly grabbed a knife and threatened to kill him.

In the docs, Ashley also says Lavender "grabbed my head and slammed it into the wall. She grabbed my neck and was choking me."

Ashley claims it wasn't the first time Lavender got violent with him -- alleging she also tried to choke him during a fight in June.  During that altercation, Ashley claims, "While I was grabbing for her hands she kneed me in the growing [SIC] area. My private area was throbbing from the pain."

Jantel has been ordered to stay at least 100 yards away from Ashley until the next court hearing.

After the judge granted the restraining order against Jantel -- she filed a request for a restraining order of her own against Adam ... claiming he attempted to punch her during a recent screaming match at her home.

The two are set to meet in court on August 30.

You'd think the WNBA would be desperate for spectators -- but a player on the L.A. Sparks wants one fan to stay the hell away ... and she's asking for a restraining order to make sure that happens.

Sparks center Jantel Lavender filed the request for a restraining order last week -- asking a judge to keep her ex-boyfriend Adam Ashley at least 50 yards away from her and her family at all times ... including games.

According to the docs, Adam attended a recent Sparks game and followed Jantel home -- where the two got into a screaming match and Adam attempted to punch her.

The fight went on all night -- and Jantel claims she eventually called the police to kick Adam out. Jantel claims she had to call the police AGAIN the next day -- when Adam came back to continue his "angry rampage."

A judge will decide whether to grant the restraining order on September 6.