I honestly was not expecting him to spam Work Up before attempting to massacre my team either (Thankfully he only knocked out one)! Definitely helped to have Mareep on my team, although Cheren's Pokemon never lost a turn from paralysis, haha! But the Speed drop did help. This game does a pretty good job so far with throwing the unexpected my way. After fighting a bunch of Level 9s, I was expecting Cheren's best Pokemon to be Level 11. Nope! XD
Also, I'm surprised by just how tough some of these Pokemon are to capture this early in the game! I finally had to catch an Azurill with a Great Ball after wasting four Poke Balls on them. But now Sunkern is giving me trouble! Even with a Great Ball! This was totally unexpected!
I do love the difficulty so far. It's really nice; makes the game more exciting.