On Dec. 26, in a prime-time game, the Dallas Cowboys beat Washington by 42 points. While the hype after that game was out of control, it was justified. The Cowboys looked Super Bowl-worthy.

A few weeks later, that same team went one-and-done in the playoffs.

The Cowboys are on an improbable streak. They haven't played in a conference championship game since the end of the 1995 season. This failure will linger for a long time. It's a team that had the offensive and defensive stars to make a deep run, but they were outplayed on their home field by a San Francisco 49ers team that barely made the playoffs. The Cowboys' season is over after the 23-17 wild-card round loss.

Dallas made a run, sparked by Jimmy Garoppolo's awful fourth-quarter interception that helped pull the Cowboys to within six points. Dak Prescott had a chance to drive his team for the win in the final three minutes, but on fourth-and-11 the 49ers blitzed and got pressure, and Prescott's desperation pass to Cedrick Wilson fell incomplete.

The 49ers couldn't run out the clock after that and had to punt. Dallas had a small chance to drive 75 yards in the final 32 seconds, but the Cowboys couldn't stop the clock after a Prescott run to the middle of the field. An official bumped Prescott trying to get the ball set, which threw Prescott off as he rushed to spike it. It was a poor decision to run Prescott that late in the game with with no timeouts left. Time ran out and the Cowboys' season was over.

The 49ers have been on a roll and could end up making a Super Bowl run. We thought the same about the Cowboys just a few weeks ago.

Cowboys suffer devastating loss

The energy on Sunday for the Cowboys was bad from the start. The 49ers had a dominant drive to start the game and Eli Mitchell scored for a 7-0 lead. The Cowboys lost 13 yards on their first drive and the 49ers responded with a field goal.

There were moments when the 49ers seemed willing to let Dallas back into the game. They settled for some field goals. They had a brutal roughing the punter penalty to start the second half. But the Cowboys still languished behind. They trailed 16-7 in the third quarter when Prescott threw an interception to K'Wuan Williams. On the next play Deebo Samuel ran 26 yards for a touchdown and the Cowboys were in a big hole.

Dallas had a shot late in the fourth quarter after Garoppolo threw the interception, the Cowboys cashed in and then got the ball back after a great tackle by linebacker Leighton Vander Esch on a third-down Samuel catch. But a well-timed 49ers blitz on fourth down on the ensuing drive led to Prescott throwing incomplete, ending that chance. Dallas had one more opportunity but its desperation drive came up short.

All the potential issues for the Cowboys bit them Sunday. Head coach Mike McCarthy didn't have a lot of answers. Ezekiel Elliott looks like he won't rebound to the running back he once was. Prescott had a quiet day. Dallas thrives off big plays on defense and the Cowboys' playmaking stars didn't generate many. Cornerback Trevon Diggs, who led the NFL in interceptions but gave up a lot of yards as well, didn't have a great day. There were way too many penalties, including an illegal hands to the face with less than five minutes left on a third-and-12 that allowed the 49ers to keep a crucial drive alive. The Cowboys were sloppy and were outplayed by the 49ers, who looked like the better team all afternoon.

One sequence summed up the Cowboys' effort. They ran a nice fake punt in the fourth quarter. Then they made the confusing decision to leave the punt team on the field, presumably in an effort to confuse the 49ers. The Cowboys tried rushing their offense on the field, but the 49ers were allowed to substitute too and Dallas took a delay of game. It was a smart play followed up by a totally needless mistake.

After that win over Washington, it seemed inconceivable Dallas would be done before wild-card weekend was over. It'll be a long offseason.

49ers continue their hot streak

The 49ers are playing as well as anyone. They have won eight of 10, including an overtime win in Week 18 at the Los Angeles Rams just to get in the playoffs.

The things they do well all clicked against Dallas. They ran the ball well. They got big plays from one of their playmakers, this time Samuel. The defense was very good, limiting Dallas' run game and pressuring Prescott often. A team that can run it like the 49ers, get a few big plays a game from their offensive stars and get after the quarterback can be a problem in the playoffs. They were for the Cowboys on Sunday.

There are flaws. On Garoppolo's horrendous fourth-quarter interception, he badly overthrew Trent Sherfield and it was returned deep into Cowboys territory, and Dallas cashed it in with a touchdown. It was a hideous mistake at the exact wrong time for Garoppolo, but that's a reason the 49ers already drafted his successor. He can melt down at the worst time.

That made the 49ers sweat. But San Francisco's defense came up with the stops it needed at the end. It doesn't do the Cowboys much good to know they were close to a win over a hot 49ers team. They were expected to win and start a postseason run. But their offseason begins before the NFC championship game, yet again.