Baylor and TCU first played each other in 1899, when both Christian schools were still located in Waco.

Even with a 10-year hiatus between games after more than seven decades together in the Southwest Conference, this is still the most-played series for both schools that are league rivals again. The series is dead even at 51-51-7 and 1-1 in the Big 12 Conference.

Through all those games over all those years, not one was played when both teams were ranked — until Saturday. And this is epic, a top 10 matchup of the Big 12's only remaining undefeated teams when No. 5 Baylor (5-0, 2-0 Big 12) is home against No. 9 TCU (4-0, 1-0).

"We understand the significance of this ballgame," Horned Frogs coach Gary Patterson said.

"It's like a cross-town rival, like in high school," Baylor cornerback Terrell Burt said. "I don't think they like us, and we don't like them."

The intensity of the rivalry has seemingly increased exponentially just in this decade.

After losing 45-10 at TCU in 2010, Baylor players were heckled with "Way to go Big 12!" on their way up the steps back to their locker room.

In an opener the following year at Waco, with TCU coming off an undefeated season capped by a Rose Bowl victory, the Heisman Trophy season of Bears quarterback Robert Griffin III got started with a wild 50-48 victory. RG3 caught a 15-yard throwback pass to convert a third-and-10 on the drive that led to the game-winning field goal after Baylor had blown a 47-24 lead in the fourth quarter of a nationally televised game under the Fright night lights.

"You can't deny the time that we were away from each other, the TCU fan, it was a burr in our saddle that Baylor was in the Big 12 and we were not," said Jack Hesselbrock, a TCU graduate and longtime athletic administrator at the school. "And then I think there was ... maybe envy at our success in the other conferences, because it did reach a very high level with both BCS games."

Baylor lost more twice as many games as it won during its first 16 seasons in the Big 12, going 60-126 overall with only two bowl appearances from 1996-2011.

TCU was a member of three different conferences in that span, winning or sharing seven league titles in the WAC, Conference USA and the Mountain West. The Frogs were 139-57 overall with 13 bowl games, and won three consecutive MWC championships without a league loss before moving to the Big 12 in 2012.

It is less than 90 miles on Interstate 35 between Baylor's brand new on-campus stadium along the Brazos River in Waco, and TCU's stadium in Fort Worth that was completely redone before the 2012 season.

But the series began when both schools were in Waco. The neighboring teams had already played 25 times by 1910, the year TCU moved its campus to Fort Worth.

The Bears have won 21 of their last 22 home games, the lone loss being to TCU in their first Big 12 meeting two years ago.

On the way to winning its first Big 12 title last season, Baylor won 41-38 at TCU. Patterson was irate about Bears safety Ahmad Dixon, who was ejected from the game for targeting Trevone Boykin, then a receiver and now the starting quarterback. That led to an awkward postgame exchange between the coaches, and Patterson angrily addressing the situation at length with reporters after the game.

"I don't see any rivalry at all," Briles said this week when asked to characterize his relationship with Patterson.

Even Patterson this week downplayed the perceived riff between the two coaches.

"I'm not the most popular guy in Waco, and that's OK," Patterson said. "But as a person, I have no problem with coach Briles. I like him, love his wife. Great people. I like his family."

But not the Bears. Not for those three-plus hours on Saturday.