Missouri fans celebrate Kirsten Mack’s grand slam as Kansas University’s Shannon McGinley watches it sail over the fence in the Tigers’ 7-6, NCAA regional-clinching victory on Sunday, May 17, 2015, in Columbia, Mo.

Columbia, Mo. ? Kansas University’s softball team continually applied pressure on Missouri in Sunday’s NCAA regional championship, but the Jayhawks never delivered the big hit.

Indicative of that was the fact that in KU’s biggest inning, a four-run sixth, its only hits were a pair of infield singles.

The Jayhawks stranded 15 runners in a 7-6 season-ending loss at University Field.

“Obviously, we’re disappointed,” Kansas coach Megan Smith said. “We think we competed well, and I think we had opportunities to beat Missouri, but it’s certainly another step forward (for KU’s program).”

Kansas (40-15) was seeking its first regional championship since a trip to the Women’s College World Series in 1992.

KU is 0-3 against Missouri in postseason games the last two years. Overall, the Tigers have won 10 straight against their Border War rivals. Missouri (42-14) won a regional for the seventh time in the last eight seasons.

KU, which before last season hadn’t made the NCAA Tournament since 2006, advanced a stage further than in 2014. The Jayhawks went 2-2 in the regional this year after going 1-2 a year ago.

“Everything is a little step toward building our program even higher than we already have,” KU senior pitcher Alicia Pille said. “… I’m disappointed, absolutely, but so proud of us.”

The deck was stacked against the Jayhawks on Sunday.

Missouri beat KU 5-3 in Saturday’s second round, requiring KU to advance to the championship through the backdraw. That meant Kansas would have to beat MU in back-to-back games in the championship round to win the title. Missouri needed to win only once, and it took care of that without needing to go to an elimination game

Pille, KU’s ace, had thrown all 20 innings the first two days of the regional, and she returned to the pitcher’s circle for the championship.

Kirsten Mack knocked Pille out of the game with two outs in the third inning when she launched a grand slam through the teeth of a strong wind and into the shrubbery beyond the left-field wall to put Missouri ahead 7-2. Mack had hit an RBI double as part of Missouri’s three-run second inning.

Pille, who threw 344 pitches during the regional, didn’t think fatigue was the biggest contributor to her shaky outing.

“They had already seen me for seven innings (on Saturday), and it just wasn’t my time,” Pille said.

Sophia Templin tossed 4 1/3 innings of scoreless relief to allow KU the chance to rally.

Like Pille, Missouri ace Tori Finucane was pitching for the third time in three days.

Jessie Roane and Erin McGinley each hit an RBI single in the first inning to stake KU to a 2-0 lead. Finucane exited after issuing back-to-back walks to start the second inning.

But the Jayhawks struggled to solve reliever Cheyenne Baxter, Missouri’s soft-tossing No. 3 pitcher who earned the win by throwing 4 2/3 innings. She didn’t allow a run until KU plated four unearned runs in the sixth.

Baxter retired the first two batters in the sixth before Chanin Naudin reached on second baseman Sami Fagan’s error. MU committed another error later in the inning. Briana Evans’ bunt single was the only run-scoring hit of the inning.

Paige Lowary, Missouri’s No. 2 pitcher who hadn’t pitched the first two days of the regional because of illness, entered with two outs in the sixth with the bases loaded and the Tigers clinging to a 7-5 lead. Lowary promptly walked Chaley Brickey on four pitches to push KU within a run, but she retired Maddie Stein on a fly out to end the inning.

Lowary worked around a one-out walk in the seventh to earn the save.

The Jayhawks stranded the bases loaded in the first, second, third and sixth innings. Kansas left at least one runner on base in every inning.

“We fought to the end, fought to the end,” Smith said. “That’s what our team has done all season.”

Missouri 034 000 0 — 7 8 3

Kansas 200 004 0 — 6 7 0

W — Baxter, 3-1. L –Alicia Pille, 25-8. Sv — Lowary, 4.

2B — Benovese, Mack, MU; HR — Mack, MU.

Kansas highlights — Erin McGinley 2-for-4, R, RBI; Chaley Brickey 1-for-3, R, RBI; Taylor McElhaney 1-for-1, RBI; Sophia Templin 4 1/3 IP, 4 H, 0 R, 0 BB, 1 K.