This is from memory, so I might've messed a few things up, but this is roughly how the final battle went:
Turn 1:
P2 swaps out Zapdos for Metagross. P1's Smeargle uses Fake Out on Cress. Cress flinches, P1's Zong uses Trick Room.
Turn 2:
P2's Metagross uses Bullet Punch on Smeargle, who survives with 1 HP. P1's Smeargle uses Dark Void. It hits both and wastes both berries, Zong uses Hypnosis which hits Metagross successfully. Cress finishes Smeargle off with Psychic. P1 sends in Snorlax.
Turn 3:
P1's Bronzong is switched out for Metagross. Snorlax uses Belly Drum, regains 30% health with Sitrus. Cress uses Psychic on Snorlax for insignificant damage. P2's Metagross snoozes.
Turn 4:
Lax uses Return on Cress for about 95% damage. P1 Metagross uses Hammer Arm on P2 Metagross, Speed goes down. Cress uses Psychic on Snorlax again. P2's Metagross continues to sleep.
Turn 5:
P1's Snorlax uses Fire Punch on Metagross for the kill, and P1's Metagross finishes off Cress with Bullet Punch. Zapdos and Latios are sent in. Trick Room ends here.
Turn 6:
Metagross uses Bullet Punch on Latios, knocking off about half of its health. Latios uses Draco Meteor, which nearly kills Snorlax. Zapdos finishes Snorlax off with Thunderbolt. Bronzong is sent in.
Turn 7:
Metagross uses Bullet Punch on Latios for the kill. Zapdos uses Thunderbolt for just over 50% damage on Metagross. Bronzong uses Hypnosis on Zapdos.
Turn 8:
Metagross uses Bullet Punch on Zapdos for roughly 30% damage. Zong uses Psychic for something like 15% damage, Zapdos sleeps.
Turn 9:
Metagross uses Bullet Punch again for another 30%-ish damage. Zapdos wakes up and just barely manages to finish off Metagross with Thunderbolt. Bronzong uses Psychic again.
Turn 10:
Zapdos uses Detect to get lefties recovery. Bronzong uses Trick Room.
Turn 11-end:
From here on out it was something of a stallout between Bronzong, who tried to keep Zapdos to sleep with Hypnosis while wearing it down with Psychic, and Zapdos who would try to detect for lefties recovery while using T-bolt for offense. Ultimately, Zapdos only got 1 Thunderbolt in on Zong for roughly 35% damage (which didn't have leftovers), but Bronzong finally got a sp def drop and finished Zapdos with Psychic.
I'm not 100% sure if turns 7-9 are correct, but the final stall definitely started with Zapdos at something like 30-40% after a few Bullet Punches vs Bronzong at full health.
I don't remember the Junior division finals quite as well. The winner (an American called Knight) led with Bronzong and Hippowdon, and used a Bronzong set with Safeguard/Swagger (he also used Trick Room on his Zong to stop the enemy from setting up TR). His opponent led with Bronzong/Dusknoir and used pretty much the same strategy; fast-forward a bit into the battle, it's +2 Metagross and a Snorlax (Knight's opponent) versus Bronzong and Garchomp (Knight, who still had 1 more Pokemon in reserve). Garchomp uses Earthquake and deals a fair amount to Metagross and Snorlax, but Metagross uses Ice Punch. Ice Punch misses due to Sand Veil, though, and Garchomp KO's both next turn, giving Knight the win.