MIAMI — Vernon Davis was, of course, absolutely certain.

Certain he could have changed the outcome of Sunday's game.

And you know what? In this case, Davis' supreme confidence wasn't misplaced.

The game and the 49ers' modest winning streak were both lost in explosive fashion, as Miami held on for a 14-9 victory. On the 49ers' final play, linebacker Joey Porter beat Barry Sims to sack Shaun Hill.

Porter was so excited by his lone standout play that he launched his helmet halfway to Key West and drew a flag. That's the kind of crazy act Davis might be expected to perform.

A frustrated Davis was on the sideline watching.

"I almost cried," he said. "If I was out there he wouldn't get that sack, I promise you."

The winner of the highly anticipated Porter-Davis cage match was Davis. Matched up on Porter several times during the game, Davis contained the league's sack leader. Despite a trash-talk contest that Davis said "you'd have definitely enjoyed," had it been audible and which began 47 minutes before kickoff in pregame warm-ups, Davis kept his composure. And he kept Porter off Hill.

But on the last play, when someone really needed to keep Porter off Hill, Davis wasn't there to do it.

"It was a formation thing," Davis said. "Mike Martz likes to go four wideouts and take the tight end out."

Sunday, the 49ers played another highly entertaining game. Though they are assured of a sixth straight losing season, their watchability factor has skyrocketed since Mike Singletary took over as coach. They are competitive, interesting and not the predictably dull slackers that we've been subjected to for so many years.

Though it was another loss, bringing his record as a head coach to 3-4, it was another game to bolster Singletary's resume. The man has changed things and anyone who doesn't want him to remain coach should consider the old proverb:

A bird in the hand is worth not going through another mind-boggling York coaching search.

But the 49ers still have problems. Their final drive was another exercise in frustration. Twice in six weeks the 49ers have had the chance to win on the road in the waning seconds only to make like Plaxico Burress and shoot themselves in their own appendage.

And, as in Arizona, the loss leads to more questions about the 49ers' late-game composure and the offensive strategy of Mike Martz.

This time the 49ers had time their final drive. They moved the ball down the field as they had all day — despite the absence of Frank Gore. But after a 13-yard completion, Hill spiked the ball on the Miami 21-yard line to stop the clock with 1:18 to play. That's what he couldn't do in Arizona. But Sunday, with that much time, you could argue that the 49ers needed downs more than time.

"We were just trying to stop the clock," Singletary said. "So we could regroup and figure out what we wanted to do with those next three downs."

But the strategy didn't work. The 49ers lost a down and couldn't execute on their remaining three.

"We were having a difficult time getting those calls in," Singletary said. "The communication wasn't the greatest."

Hill said the crowd noise made it difficult to get in the right plays.

And the final three downs were: incompletion, incompletion, and the deciding Porter sack. The one Davis felt he could have prevented.

"It would have been just like the whole game," Davis said. "He wouldn't have got nothing."

Earlier in the week Davis launched the Porter festivities by saying: "I'm pretty sure I've gone up against a lot of other linebackers/defensive ends who are better than him. And I've pretty much won every battle."

In pregame warm-ups, Porter got in Davis' face and what Singletary predicted would be a "jaw-jacking competition" was on.

"He wanted to start something up," Hill said of Porter. "Vernon was really getting disrespected and I thought he handled it well."

Davis proved his worth as a blocker. He even proved his value as a running back, rushing for an 11-yard gain. But he had some key receiving mistakes, including a ball clanking off his hands in the first half and failing to turn for a ball on a third-and-six hot read in the fourth quarter.

But he didn't lack for bravado.

After claiming he could have prevented the determining sack, Davis circled back to a group of local reporters, accompanied by two 49ers media-relations staffers. Davis isn't enough of a receiving threat on the field to draw a double-team but he's worthy of one in the locker room.

"I want to acknowledge," he said contritely, "that the offensive line did a good job when I wasn't in there."

But in his heart, he was positive he could have changed the outcome of the game.

And, this time, Davis may have been right.