MJ Knighten knocks in the winning run in the bottom of the seventh to give Nebraska a 3-2 victory over Louisville. (0:37)

BYU's 12th consecutive appearance in the NCAA tournament (and the school's long-standing abstention on religious grounds from Sunday competition) continued what now feels like an informal tradition of a single softball regional beginning a day ahead of the rest of the bracket.

While 60 teams will take the field for the first time Friday, the Columbia regional commenced Thursday with games between No. 15 Missouri and BYU as well as Nebraska and Louisville.

If you didn't catch the games, here is what you missed.

Nebraska 3, Louisville 2

MJ Knighten had enough left to run to first base, but rarely has walk-off been a more accurate description than on the ailing Nebraska star's winning hit in the opening game of the Columbia regional. Perhaps it took a Kirk Gibson-like moment for her season to finally get its due.

While the tournament utilizes a double-elimination format, an unseeded team that loses the opening game of a regional is effectively playing spoiler for the remainder of its stay. It is difficult for unseeded teams to win regionals, period, but since the tournament went to its current format in 2005, only two unseeded teams lost a regional opener and then won four in a row to advance. One was Jacksonville State in 2009. The other was Nebraska in the 2014 Columbia regional. Lightning rarely strikes twice in the same place.

So, yes, seasons were on the line as Louisville and Nebraska crept toward extra innings tied 2-2 on Thursday.

Such circumstances push teams to test conventional wisdom, which explains the sight of Louisville intentionally walking Kiki Stokes in the bottom of the seventh inning to load the bases and bring Knighten to the plate -- the same Knighten who is tied for second nationally in home runs.

In addition to the logic of setting up a force play at any base, Louisville elected to pitch to a player who appeared to injure her ankle on a slide in the first inning and could be seen on the television broadcast moving with a pronounced limp for the remainder of the game. It made sense from a tactical standpoint, but in the case of a player whose slugging exploits this season weren't enough to land her on the list of 25 finalists for national player of year, it looked like one more challenge placed in front of her. She didn't need a homer. She just needed a hit.

It's safe to assume she will trade a night spent with a lot of ice for the all-important place on the preferred side of the bracket that the Huskers earned with the win.

No. 15 Missouri 9, BYU 0 (5 innings)

In one sense, No. 15 Missouri's win against BYU was as predictable as results come. Seeded teams are now 161-16 in regional openers since the move to four-team regionals in 2005, and 48-1 the past three seasons. Well-placed in the RPI, BYU offered a significantly better resume than the typical fodder in those games but still faced long odds for an upset.

What lent the evening an air of unpredictability, at least beforehand, was summed up by the hot air balloon that floated by the stadium in the second inning with a banner that appeared to be in support of embattled Missouri coach Ehren Earleywine, currently the subject of an internal school investigation that had been protested by the team's players until this week.

The last time a seeded team entered the NCAA tournament with a similar degree of off-field drama was probably 2012. In that instance, fifth-seeded Florida dismissed three starters on the eve of the tournament and then lost its opener en route to a discombobulated regional exit.

But with the balloon likely still in range Thursday night, Missouri's Amanda Sanchez hit a grand slam down the right-field line to extend her team's lead to 7-0 in a game that was never in doubt. With Paige Lowary pitching well and the lineup's top four of Taylor Gadbois, Emily Crane, Sami Fagan and Sanchez combining for six hits, five runs and eight RBIs, Missouri looked less like a team under any kind of cloud and more like a team distinctly under-seeded at No. 15.