Fernando Tatis Jr. Shakes Butt After San Diego Padres Advance To NLDS

The San Diego Padres booked their ticket to the NLDS following a 5-4 win against the Atlanta Braves on Wednesday ... and their star utility player Fernando Tatís Jr. was certainly in the moment -- letting his hips loose and enjoying the postgame clubhouse festivities!!!

Per tradition, the Padres players and coaches popped champagne and cracked open some cold ones to commemorate the victory -- and Tatís Jr. was in great spirits after sending the Braves packing.

The 25-year-old -- who went an impressive 4-for-6 at the plate with two RBIs and a homer in the two-game sweep -- decided to shake his backside for his teammates while enjoying a Budweiser.

Tatís also broke out into a little jig ... and his teammates played the ultimate hype men!!!

Just before that ... David Peralta got the party started by giving a speech to the Padres -- saying this was just the beginning of their World Series chase.

"We got to stay together," he said. "This is a first step, we got three more guys stay together.  We're a great team, I believe in all of you guys. We're gonna go all the way, baby!"

Now the team has a date with Shohei Ohtani and the Dodgers starting on Saturday -- and the team was sent off in style ... with the ballpark breaking out into a "Beat L.A." chant.