why tier 3 vs tier 5?

Ectar:     If the enemy has a tier 5, then you also have a tier 5. If you're in a tier 3 don't try to fight the tier 5 heavy head on, that's their main strength.  Instead try to get beside and behind them to get your shots.   Tier 8 can easily do well in a tier 10 match so long as the player knows their tank and knows the map.  You should also know what you can't and can't penetrate and use that to your advantage. Again looking for flanking shots and shots from the rear. The enemy tier 10s should be focusing on your tier 10's or tier 9's.   Beig the lower tier tanks in match ups like that is all about supporting. You can't lead the charge.