This story was excerpted from Jessica Camerato’s Nationals Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox. Kyle Finnegan had been in this situation before. It is not uncommon for him to come off the mound and express his desire to return for another inning. That competitive drive, after all, is a key factor in late-game success. But the vibe was different on Friday night. The right-hander’s fervent belief he could clinch the Nationals’ roller coaster win against the Phillies was unmistakable. “There’s some days we’ll have a conversation and he’s…