Key takeaways: Padres 7, Marlins 3

SAN DIEGO — The Padres aren’t merely sneaking up to the postseason party. They’re kicking down the door. San Diego has won 13 of 14. No team in baseball is hotter. Not all that long ago, the Padres were on the outside of the playoff picture, looking in. Now — after Sunday’s 7-3 victory over the Marlins — they’re on the verge of a clinch. Get tickets to watch the Padres face the D-backs! Here’s some instant reaction from Petco Park: Champagne on ice In their 58-season existence, the Padres have never reached the postseason in three straight years. They…