It didn't matter that it was one of the most electric crowds in Rattlers history on Saturday night at Gila River Arena.

With fans waving towels, booing every call against the home team, the Rattlers take a bunch of "what ifs" into the offseason after squandering a 10-point, second-half lead and losing to the Sioux Falls Storm 56-53 in the United Bowl before 14,635 fans.

The Rattlers (15-1), losing their only game of the season, couldn't make stops on the Storm's third downs. They didn't make a defensive stop, period.

And they gave game MVP Lorenzo Brown Jr. way too much time to find receivers to pick them apart.

Once again, the Rattlers failed to win a championship game at home. They are now 1-4 at home in championship games with the only victory at home coming against quarterback Kurt Warner and the Iowa Barnstormers in the 1997 ArenaBowl.

Since then, they lost at home in league title games to San Jose, Jacksonville and in 2016 in their final Arena Football League game to Philadelphia.

This time, coach Kevin Guy felt he was coaching against two teams – the Storm (14-3) and the referees, whom he blasted in his postgame interview.

"If that's our best crew ...," Guy said. "Every time we made a key play, there was some stupid penalty. Ticky-tack. It was ticky-tack. They're in the locker room before the game, saying, 'This is big boy football and we're going to let you play,' then they call ticky-tack stuff on key downs. We'll address it in the offseason. But I'm fed up."

The biggest call that went against the Rattlers came with a one-touchdown lead in the first half when Devin Cockrell's interception was wiped out by a roughing-the-passer penalty. Instead of going up two touchdowns, the Rattlers were tied moments later.

"Ticky-tack," Guy said. "Flopping. Terrible call. The one that really changed the game was our fourth down. We went for it. Everybody in the house saw it, it was pass interference. He all ran right through the receiver. So it is what it is.

"The referees took us out of the game."

Sioux Falls was called for one more penalty than the Rattlers, who were penalized six times, four in the first half, for 59 yards. The Storm was penalized seven times for 47 yards.

The Rattlers made the game interesting in the final minute with quarterback Drew Powell scoring from 11 yards out, then tailback Jabre Lolley adding the two-point conversion. But the Rattlers were called for off-sides on the onside kick, nullifying the Rattlers' recovery.

"We get an onsides kick and same thing," Guy said. "Did he break the plane? Maybe. Was his foot down on the ground on the other side, no. All these other damn leagues, you can challenge anything. But we don't want to be held accountable in this league. We want to protect the refs, instead of getting the call right."

Guy brought up other examples.

"We should be able to challenge everything on the field," Guy snapped. "The referees should be held accountable, just like the coaches and players are."

In the end, the Ratters put no pressure on Brown, who could survey the field before finding open targets all night. The last one was the dagger -- a 15-yard completion to Damian Ford to the Rattlers’ 1 with 35 seconds left.

Game over.

Brown was 15-of-19 passing for 200 yards and five TDs.

"They create pressure and force you to make mistakes," said Brown, who was playing in front of the biggest crowd he ever had seen as a pro. "I said, 'We've got to be solid up front and pick up the blitz.' That's what we did. Some of those third-down plays, I was going second, third read. It was like a scrimmage drill."

As IFL Commissioner Mike Allshouse got on the public-address system to present the championship trophy to the Storm, the fans who were left booed.

"Oh man, it's very frustrating," said receiver Jarrod Harrington, who was the Rattlers' best player, showing why he won the league's Most Improved Player of the Year Award with his 58-yard kickoff return and some highlight-reel runs after catches.

"We lose it at the end. We can't blame anybody but ourselves. Yeah, the refs played a part in it. But at the end of the day, we had opportunities to win the game and we didn't execute."

Powell declined coming out for the postgame interviews. He struggled in the second half. It was one of his worst games since joining the Rattlers in late April. The Storm had a great plan against him after seeing how he beat them in last year's United Bowl when Powell was league MVP for the Iowa Barnstormers.

Powell was 16 of 21 for 166 yards and two TDs. But he was sacked three times, losing the ball one of them with 10 minutes left that led to the Storm taking their biggest lead, 56-45 with 3:38 left.

Guy, who has won four championships since he came to the Rattlers in 2008, fell to 0-3 in home championship games, losing to Jacksonville on the last play at Talking Stick Resort Arena in the 2011 ArenaBowl.

They fell to 0-2 in championship games played in Glendale. The Philadelphia Soul loss was in Glendale in 2016.

Meanwhile, the Storm captured their 11th championship and first since 2016.

The Rattlers didn't get the Storm into a fourth-down situation until six minutes remained.

But on fourth-and-1 from the Rattlers’ 16, Brown pitched to Brandon Shepherd for a first down. That led to 9-yard scoring pass from Brown to Kent Shelby.

The Rattlers' offense bogged down for the first time in the half in the final minute when they got as close as the Storm 3, before Powell lost control of a snap and had to take an 8-yard sack.

He called timeout just in time for Jimmy Camacho to drilled a 31-yard field goal as time expired to give the Rattlers a 31-28 lead.

The only turnover was on a Storm kickoff that Dez Stewart recovered at the Storm’s 5. That was turned into a Jamal Miles' 2-yard TD run and a 14-7 Rattlers lead.

The Rattlers made "Undefeated" shirts after finishing their first regular season unbeaten. But it didn't end that way.

"I didn't feel any extra pressure," Guy said. "I didn't think our locker room felt any extra pressure. We had two weeks of practice. Look, there are three teams out there. There is the team we're playing. There is us. And the referees.

"Yeah, the refs are part of the game. They're supposed to be bringing their best. And they didn't have their best night."

To suggest human-interest story ideas and other news, reach Obert at richard.obert@arizonarepublic.com or 602-316-8827. Follow him at twitter.com/azc_obert.

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