This is where we separate the men from the boys. Are you capable of changing your game plan to defeat your opponent or are you going to be a one trick pony and fight everyone the same.
If I was Brown I would engage the clinch early and drive him into the fence. He needs to give Lombard no space and at the same time make him work hard. Drill for strikes against the cage.. lean on him.. go for takedowns. Then as Lombard starts to slow down you start to fight with him.
The more Brown forces Lombard to work the more Brown is at an advantage. He has a huge cardiovascular advantage and he may as well attempt to start to make that the story of the fight early and often while getting inside and leaving no room for Lombard to create distance and use his explosive speed.
If Brown is very smart? He could win this. He needs to slow Lombard down early enough to potentially either A. Finish the fight late or B. Be in position to at least take the 2nd and 3rd rounds.
If he can slow Lombard down enough in the 1st round there is a chance he could still win the 2nd and 3rd but if he let's Lombard pace himself he could be in serious trouble and might have to go for a late stoppage which isn't where you want to be.. taking chances and pressing to finish a Lombard..