The Tampa Bay Rays couldn't have picked a better time to get the big hit that has largely eluded them this post-season.

But even for one of the most innovative clubs in baseball, how it happened in Game 4 of the World Series against the Los Angeles Dodgers on Saturday night was far from how anyone could have drawn it up.

It started with Brett Phillips, who stepped into the batter's box with two outs, two men on and his team trailing 7-6 in the bottom of the ninth.

Phillips, who was left off the American League Championship Series roster and was hitless since 25 September, had entered the game in the top of the inning as a defensive replacement. He wasn't expected to be the guy in the spot to have to deliver, but there he was.

Phillips did his job with a looping single to right, and from there, anarchy ensued. When the dust settled, the Rays had won 8-7, completing an improbable comeback to forge an unlikely 2-2 tie in the best-of-seven series against the heavily favoured Dodgers at Arlington, Texas.

Kevin Kiermaier came around to score from second on Phillips' single; but behind him Randy Arozarena seemed dead to rights at the plate after doing a full somersault on his way home.

However, through a series of Dodgers misplays that culminated with catcher Will Smith having the ball get away from him, Arozarena dove home for the wild walk-off win.

"The baseball gods were on our side," said Kiermaier. "I was the happiest man on the planet to see Randy score so the game could be over with. I couldn't take any more from that point on."

"I think I lost 10 years on that last play," added teammate Brandon Lowe.

"Man, baseball is fun," Phillips offered succinctly.

Los Angeles centre fielder Chris Taylor was charged with an error on the final play.

"It was like an [imperfect] storm," said Dodgers manager Dave Roberts. "Just unfortunate."

The ninth inning was far from the only hectic part in a game that turned into a back-and-forth slugfest in the late innings. Corey Seager had given the Dodgers a 7-6 lead with an RBI single in the eighth.

He finished with a home run and four hits, as did Justin Turner, as all seven Los Angeles runs were scored with two outs.

"It didn't go our way today," said Dodgers pitcher Kenley Jansen (0-1). "It was a tough battle. We're all confident we're going to come back and turn the page."

Game 5 will take place Sunday.