PHILADELPHIA — Nobody said it was easy. The Mets are enjoying their best regular season since 2006 and are on pace to win 100 games for just the fourth time in franchise history. But they enter the weekend with a slim 3.5 lead over the Braves in the National League East, leaving no guarantee that their blistering pace will lead to a division crown or first-round bye in the re-formatted playoffs. They now have four games with the Phillies in roughly 48 hours.