The 49ers are 6-0 after defeating the Los Angeles Rams and Washington on their two-game road trip. Now they return home to take on the 4-2 Carolina Panthers. The Panthers are coming off a bye week but have won their last four games after Kyle Allen replaced Cam Newton at quarterback when Newton went down with a foot injury.
The game might be the toughest test of the season for the 49ers. Here are the three matchups that’ll decide Sunday’s game:
Robert Saleh vs. Kyle Allen

The 49ers defense is ranked No. 2 in the NFL behind the New England Patriots in yards per game and points per game. A large part of that is due to the scheme Saleh puts together. His defensive line allows him to rush just four while dropping seven into coverage. He has shown the ability to adjust as well, getting beat on the run on the first drive of the game the last two weeks, then shutting it down for the remainder of the game.
Allen has been fine in his four starts this year, going 4-0 with seven touchdowns and no interceptions with 901 yards for a passer rating of 106.6. He’s struggled dealing with pressure though. He’s been sacked 10 times and fumbled six times.
Pressure has been Allen’s weak point, and the 49ers have been excellent at getting after opposing quarterbacks. Saleh will have to come up with some different blitzes and exotic pressure schemes to throw off Allen and put him in difficult spots he hasn’t been in yet.
Kwon Alexander vs. Christian McCaffrey

Alexander has done a little bit of everything for the 49ers’ defense this season. He’s second on the team with 30 tackles and also has 0.5 sacks, an interception, a forced fumble, and four pass deflections. He’s been one of the best, if not the best, addition the 49ers made in the offseason.
Just like Alexander, McCaffrey can do everything for the Panthers’ offense. He’s averaging 103 rushing yards per game and 50.8 receiving yards per game this season. He’s carried the load for Carolina by leading the team in carries and receptions.
Alexander will be zoned in on McCaffrey in the rushing attack and the passing game. He doesn’t necessarily have to stop McCaffrey, but if he can hold him to manageable numbers, the Panthers offense will need to find a different means of productivity.
Justin Skule vs. Mario Addison

Skule has played well in place of the injured Joe Staley. Skule has allowed only two sacks on 316 snaps since taking over at tackle in Week 3. He’s also excelled in the run game to open holes for Matt Breida and Tevin Coleman.
He does face his toughest blocking assignment this season against Addison. Addison leads the Panthers with 6.5 sacks and has been the best pass rusher on a defense that leads the NFL in sacks. His sack total is sixth-best in the NFL.
Skule will have his hands full with not just Addison, but also rookie pass rusher Brian Burns, who will rotate with Addison on the right side. If Skule struggles against Addison, look for an additional to help with blocking, or Kyle Shanahan to start leaning on quick pass plays, runs and play action to try and relieve pressure on Garoppolo.