SANTA CLARA, Calif. (AP) -- There is a much different feeling and outlook for the San Francisco 49ers defense this December than a year ago.
The unit is again ranked near the top of the NFL in several major defensive categories, but instead of limping toward the end of the season, San Francisco is surging to the finish.
''Healthy plus hungry,'' safety Donte Whitner said. ''Hopefully it equals Super Bowl.''
The Niners are as healthy as they have been this season, and there is little question the veteran, star-laden unit is hungry. San Francisco has been dominant on the defensive side of the ball during a four-game winning streak that dates to the end of November.
The 49ers limited Tampa Bay last week to 183 total yards, the fewest the NFL's third-ranked defense has allowed this season. It was a performance typical of their recent play as the 49ers harassed Mike Glennon, who was sacked four times, and forced two turnovers.
The 49ers will try to continue that momentum Monday against Atlanta in a rematch of last season's NFC Championship. San Francisco would clinch a playoff berth for the third consecutive season with a win in the final game played at Candlestick Park or with an Arizona loss to Seattle on Sunday.
''We're playing like we've always played,'' said defensive coordinator Vic Fangio, whose unit finished last season ranked third in the NFL. ''We do have some new guys that have filtered in there, but a lot of the same guys are playing.
''They're playing confident and fast like you would expect being in the same system basically for three years.''
Though the rankings are similar, San Francisco's defense was in a much worse place last year. The 49ers lost All-Pro defensive tackle Justin Smith to a torn triceps in Week 15, and he wasn't the same dominant player when he returned for the team's playoff opener four weeks later.
Beginning with Smith's injury, the 49ers allowed an average of 29.6 points over their final six games, including the playoffs, a stretch that ended with San Francisco's 34-31 loss to Baltimore in the Super Bowl.
The 49ers are much better now, with Smith healthy and drawing double teams in the trenches. All-Pro outside linebacker Aldon Smith is also back in form and causing havoc next to him.
The Smiths combined for three sacks last week against the Buccaneers, continuing a trend in which San Francisco has lead the NFL in sacks per play since Week 12.
Aldon Smith returned two weeks before that after missing five games to do a stint in rehab, and All-Pro linebacker Patrick Willis also missed two games during that stretch. The 49ers haven't been the same since they returned.
''I hope I've had something to do with it,'' said Aldon Smith, who set a franchise record with 19.5 sacks last season.
Smith has 8.5 sacks in nine games this season to share the team lead with outside linebacker Ahmad Brooks.
''We're better now and healthier, and with guys being together, we just know more than we knew last year,'' he said. ''Hopefully we can get that mental and physical together and make a run for it.''
Seven of San Francisco's defensive starters made the Pro Bowl or an All-Pro team last season. With rookie first-round draft pick Eric Reid filling in capably for departed All-Pro Dashon Goldson at free safety, the 49ers are loaded and ready for another playoff run.
''Things never get easier, you just get better,'' Whitner said. ''And that's why we're playing the way we play. That's why guys are communicating the way we are.
''We're really playing good football right now. We're in better shape now than we were last year and we want to get that trophy.''
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