Roberta Vinci: Historic party pooper, instant legend in Italy …

… Inspiration to the Yankees?

“There were two underdogs in New York that won today,” manager Joe Girardi said, smiling, on Friday afternoon, giving props to surprising U.S. Open women’s finalist Flavia Pennetta as well as Serena Williams’ unlikely foe Vinci.

A third underdog did not prevail in the Big Apple. By about 7:20 Friday night, Girardi’s smile might as well have relocated overseas.

The Yankees opened their most important series of 2015 with a thud, suffering an 11-5 beatdown at the hands of the mighty Blue Jays and, with their third straight loss, falling 2 ¹/₂ games behind Toronto in the American League East.

This contest, in which rookie Luis Severino recorded his worst major league outing, reinforced what we already knew, whether we prefer using our eyes or our laptops: In this September saga, the Yankees, despite owning the larger payroll and the higher profile, are the underdogs. All the more so after learning Mark Teixeira will miss the rest of the season with a right leg fracture.

“I can understand why people might consider us the underdog. I can understand that,” Girardi said. “They [the Blue Jays] made a lot of moves. They added some pretty big names. They’ve played extremely well the second half, really ever since the trading deadline. They score a ton of runs. And so I can understand that. But you’ve got to play the games.”

The Blue Jays (80-60) own a 30-9 record in their last 39 games. In that same stretch, since July 29, the Yankees (77-62) are 20-20, allowing Toronto to pick up 10 ½ games on the Yankees. With a doubleheader Saturday, the Yankees face an opportunity to climb right back in … or stumble quite far out.

“We have to come out and pitch better tomorrow,” Girardi said, “keep the ball in the ballpark, if we want to win.”

You can see why the Jays should be regarded as the favorite. As Girardi referenced, they score runs at a ridiculous rate; their 771 runs lead the majors, and the 95-run gap between them and the second-place Yankees (676) easily marks the widest distance between any two teams next to each other in the overall rankings. The second-largest gap? The 26 runs between the Yankees and the third-place Red Sox (650).

Just in case you like your baseball canvas laid out with more science and less art, the analytical oddsmakers validate what you’re seeing. The website numberFire.com, using its simulations of the season’s duration, calculated the Blue Jays had an 81.7 percent chance of winning the division, with the Yankees at just 18.3 percent, entering Friday. The site also tagged Toronto with a 20.8 percent likelihood of capturing the World Series, with the Yankees at 4.6 percent.

That constitutes quite a disparity, given that just two losses separate the pair.

The fact Teixeira won’t be returning to upgrade the Yankees’ lineup, a probability that turned into a cold, hard fact on Friday, naturally won’t help these odds.

“I feel like this team has a chance to win a World Series. I really do,” Teixeira said. “Not to be able to be on the field for that run is really tough to take.”

Rookie Greg Bird has filled in capably for Teixeira, and the Yankees have a 13-10 record since the Aug. 17 game in which Teixeira originally sustained the injury that required three MRI exams to correctly diagnose.

As underdogs, “I think you can definitely get motivation,” Girardi said. “What it really, really comes down to is relaxing and playing the game you’re capable of, and not becoming too emotional. Not trying too hard. Not trying to make things happen.”

Of course, as with Vinci and Serena, the Yankees wouldn’t mind if the Blue Jays accepted their favorite role and assumed the accompanying pressure. Too bad for Girardi and his guys that the Blue Jays are exhibiting no such anxiety. When underdogs look like underdogs, like Friday night, the whole concept loses its charm quite quickly.