Countering Malian Pikeman as Khmer in Imperial

Long story short, I just got blasted by Malian trash. My question is, how do I prevent that from happening?

Because Malian infantry get insane pierce armor, I felt my best bet against them was to use battle elephants, who deal melee damage. He tried using Champskarls at first, and the elephants were relatively successful. The problems started when he switched to spamming pikeman.

I got destroyed by an army almost completely of pikeman and Trebs. Obviously, my battle elephants were not cost-effective options against his pikeman. I tried using arbalests (big mistake) because I underestimated the power of the pierce armor bonus and thought they would deal better with Farimba cavs than hand cannoneers; hand cannoneers are also affected by pierce armor. Not ideal.

If the right answer is teching into champions, that means I will be chasing him the entire game, as Khmer lack squires. Worse than that, my army composition of Battle Elephants and Champions is a huge gold drain compared to Pikeman and Champion, so even if I were to pin him to a spot on the map, the war of attrition is greatly in his favor.

This, by the way, was a 3v3, so reaching Imperial was extremely likely. We were both pockets and the strongest players on our team. Help plz.