Srimad Bhagavatam Canto 10, Chapter 44, Text 19

SB 10.44.19

tais tair niyuddha-vidhibhir
 vividhair acyutetarau
yuyudhate yathanyonyam
 tathaiva bala-mustikau
 
Translation: 
 
Lord Balarama and Mustika, expertly displaying numerous wrestling techniques, battled each other in the same way that Lord Krsna and His opponent did.
Srimad Bhagavatam Canto 10, Chapter 44, Text 18
Srimad Bhagavatam Canto 10, Chapter 44, Text 20