The Houston Astros appeared to be just one win away from the World Series. Instead, this ALCS has become a best-of-three affair. 

The Astros on Tuesday night in Yankee Stadium took a 4-0 lead into the bottom of the seventh inning. The final score shows 6-4 Yankees

That means the best-of-seven series is now tied at two games apiece.  

Here are eight things to know about Game 4. 

Yankees make historic comeback 

In just two innings of work, the Astros' top relievers -- Chris Devenski, Joe Musgrove, Ken Giles and Luke Gregerson -- allowed five runs on six hits. When A.J. Hinch went to the bullpen with no on and no out in the seventh, it was a three-run lead (4-1). That's not a huge lead, but handing the ball over to late-inning relievers with a three-run lead is a reasonable situation to believe the game should be in hand. 

Instead, Didi Gregorius tripled and then scored on a sac fly to make it 4-2 heading to the eighth. 

Then came The Rally. 

Todd Frazier lined a single to left to start the bottom of the eighth. Pinch-hitter Chase Headley lined what should've been a double to left-center, but he stumbled on his way to second. When the Astros threw to first, Headley quickly rose to his feet and made it to second anyway. 

Hinch would turn to his closer, Giles. Aaron Judge would double off the top portion of the wall and it was tied up. Gregorius would bleed a single just under shortstop Carlos Correa's glove to set up Gary Sanchez's go-ahead, two-RBI double to the right-center gap. 

Just like that, it was 6-4 Yankees. 

The last time the Yankees overcame a four-run deficit to win a playoff game? The Aaron Boone Game. Game 7 of the 2003 ALCS, which cost then-Red Sox manager Grady Little his job. 

Judge appears to be back

Might the worm be starting to turn for Yankees slugger Judge? He clubbed a low-lining three-run homer in the Game 3 win and then hit a colossal home run to dead center in Game 4. 

Here's a fun fact: 

His next time up, Judge came through with a clutch double to tie the game. He appears to be heating up. Prior to Game 3, he was hitting .074/.219/.111 with 19 strikeouts in 27 at-bats in the divisional round and ALCS. Now he's had two good games in a row and the Yankees have knotted the series. 

McCullers gave Astros more than could have been expected

Astros starting pitcher Lance McCullers got through six scoreless innings before Judge led off the bottom of the seventh with a solo shot to dead center. 

The final line for McCullers: 6 IP, 2 H, 1 ER, 2 BB, 3 K

Now, without context, some might see that McCullers was an All-Star this season, but there's a lot of context here. He deal with a terrible July before hitting the disabled list injured. He came back in September and still wasn't good. In his last seven starts of the regular season, McCullers had an 8.53 ERA. Opposing hitters slashed .338/.424/.485 against him. 

I often fail to mention "quality starts" as a stat because it's not very quality to go six innings and allow three runs. It's not bad, but it's a 4.50 ERA without getting into the seventh inning. I bring this up because the last time McCullers put together a quality start was also the last time he threw a pitch in the seventh inning: June 8. 

As noted in the sub-head here, the outing from McCullers was more than the Astros could have expected to get out of him. Even with the Judge homer and eventual team loss, McCullers deserves heaps of praise for this effort. 

Gurriel's enjoying a big postseason

Astros first baseman Yuli Gurriel came through with what would've been the big blow in Game 4, had the Yankees not busted through late, knocking a David Robertson pitch down the third-base line with the bases loaded in the top of the sixth. The bases cleared and Gurriel had driven home three runs, breaking a scoreless tie and putting his club in the driver's seat. 

Since defecting from Cuba, this has been Gurriel's first foray into the MLB postseason and he doesn't appear to be affected. Through eight playoff games now, he's hitting .400/.438/.567 with two doubles, a triple and four RBI. 

Gray just can't get run support

Yankees starting pitcher Sonny Gray had to be pulled after allowing two baserunners -- though one was a catcher's interference -- before getting an out in the sixth inning. Still, before that he was brilliant. Through five innings, Gray gave up just two hits while striking out four and didn't walk anyone. 

And yet, the game was 0-0 through five. 

Now, Gray's line looks a bit worse thanks to being charged with the one earned run in the sixth and not recording any outs in the sixth, but he got through five scoreless innings without getting any run support. 

It's becoming a theme with Gray in the playoffs. 

Including his two starts in the 2013 ALDS vs. Tigers ace Justin Verlander and this year's ALDS Game 1 against Trevor Bauer of the Indians, Gray has now worked 21 1/3 playoff innings in his career. While he was on the mound for those innings, his teams collectively have given him zero runs in support. 

What an unbelievable coincidence. Just jaw-dropping. 

Speaking of catcher's interference

The catcher's interference that came with Josh Reddick at the plate was the first in the history of the ALCS. 

That's interesting on its own, but keep in mind that Jacoby Ellsbury is on the other team in this series. He's the all-time leader in catcher's interference calls in both the regular season and the postseason. 

Ellsbury did pick up a CI during the ALDS. 

So did Tommy La Stella of the Cubs in that funky fifth inning in Game 5 of the NLDS in D.C. 

We've now seen three catcher's interference calls this postseason, including the first in ALCS history. 

Back up, backstops! 

Hilariously complicated CS

Aaron Judge has a "caught stealing" on his stat line, but if you didn't see the game, you'll never believe how it transpired. Check out R.J. Anderson's breakdown to get up to speed. 

Quick turnaround for Game 5

The next bout of the series is a "play it again, Sam" situation. Just like Game 4, it takes place at 5:08 p.m. ET in Yankee Stadium. It happens on Wednesday. The battle on the hill will be a rematch of Game 1, with the Astros sending lefty Dallas Keuchel (14-5, 2.90 regular season; 2-0, 0.71 postseason) against Yankees' righty Masahiro Tanaka (13-12, 4.74; 1-1, 1.38). 

Now that the series is even, Game 5 obviously becomes paramount. We could say pivotal, but that's redundant. The winner here has a big advantage heading back to Houston for Game 6, needing to just take one of two. Coming back to win two in a row after trailing 3-2 isn't all too uncommon either. We just know Game 5 is a huge one.