​The San Francisco 49ers enter Week 3 undefeated and riding one of the more efficient starts to a season in recent memory, headlined by an MVP-caliber stretch from Brock Purdy and a defense that’s making short work of opponents. Across the industry, the Niners are trending up — and in more than one case, all the way to the top spot.Here is a roundup of the top power rankings from expert pundits for Week 3.USA Today Sports: 3Only three NFL players in history have scored 50 touchdowns with two different franchises. Hall of Famers Marshall Faulk and Randy Moss and Christian McCaffrey. End of list. Impressive.ESPN: 3Purdy has been one of the league’s most productive quarterbacks since taking over the starting job in 2022. Now in his fifth season, he’s completely comfortable in coach Kyle Shanahan’s offense and coming off his best training camp. That hot start has teammates such as linebacker Fred Warner openly wondering whether Purdy can compete for league MVP honors. Through two weeks, Purdy is atop the league in QBR (94.9) despite a supporting cast that has already been thinned by injury. If he stays healthy, there’s reason to believe Purdy will post his best year yet.Sports Illustrated: 4Sure, the Rams in Australia and the Dolphins at home to follow. But the clinical dissection of both teams was enough to earn Kyle Shanahan & Co. a major boost this week. I keep thinking about something Shanahan has said that makes the team’s sustained run all the more interesting. Nearly every team in the league runs his offense, so every defense practices against it every day. The fact that the 49ers are still an elite team is more amazing than we think.CBS Sports: 3The stars continue to show up for this team, which is why it will be a serious playoff contender. With those guys on the field, and Kyle Shanahan coaching, they will be tough to beat.Fox Sports: 3The 49ers might be the most complete team in football. A terrific QB, great running game, excellent receivers, strong line, tough defense and a brilliant coach. They’ve got it all.The Athletic: 1The running back out of Indiana has more carries and almost as many rushing yards (90) as Christian McCaffrey (91) through two weeks. Not bad for a third-round pick who didn’t even get an invite to the NFL combine. And it helps make Niners fans feel better about losing promising rookie wide receiver De’Zhaun Stribling for 10 weeks due to an ankle sprain.Yahoo Sports: 3The 49ers got a good runout to start the season. They got the Rams in Australia, when Los Angeles practically blew off that trip by landing the day before the game. Then they got the Dolphins, who have the worst roster in the NFL. They blew out both teams, which shouldn’t be taken for granted in the NFL. Their point differential of +42 is dominant. They have had only two negative plays all season, not counting kneeldowns, the fewest for a team this century through two games, according to Doug Clawson of CBS. Brock Purdy is playing well, keeping the