MELBOURNE -- The 49ers just beat the Los Angeles Rams 27-7 in Australia. Here are the 49ers' grades for this performance.

BROCK PURDY: A

He was by far the best quarterback in the game. He was far superior to defending MVP Matthew Stafford, who looked old, slow and tired. Meanwhile, Purdy looked better than ever, as he threw three touchdown passes to three different receivers and ran for 29 yards himself. He also threw an interception, but he more than made up for his one mistake. This is how Purdy plays when the 49ers protect him. He seemed supremely confident the entire game. If they can keep him healthy this season, they can beat anyone.

RUNNING BACKS: A

Both Christian McCaffrey and Kaelon Black gained more than 60 yards on the ground. Black actually carried the ball four more times than McCaffrey (14 carries to 10), which is incredible, considering McCaffrey has literally refused to come off the field in the past. I guess he respects Black. At the end of the game, the 49ers gave McCaffrey carries just to pump up his stats. Otherwise, he would have seemed like the No. 2 running back behind the rookie. Can't have that.

WIDE RECEIVERS: A-MINUS

De'Zhaun Stribling went down early with what looked like an Achilles injury. The 49ers insist his Achilles is intact and say that the injury is to his ankle, but they wouldn't reveal anything else. It's unclear how much time he'll miss. But at least in this game, the 49ers didn't need him. That's because Mike Evans, Demarcus Robinson and Deebo Samuel each had at least 48 receiving yards and 1 touchdown. Evans in particular was dominant on third down and in the red zone. Robinson surprised the Rams with a deep touchdown catch when they were focused on stopping Evans. And Samuel had a great all-around game as a receiver, a runner and a returner. If these three older wide receivers can stay healthy all season, the 49ers will be tough to stop. It's ironic that the rookie receiver was the one who went down first.

TIGHT ENDS: C-PLUS

George Kittle played even though he wasn't in football shape, something he admitted to early. So the 49ers stopped forcing him passes, and suddenly the offense took off. They don't need Kittle to be the player he used to be. They just need him to block for now. He was a big reason why the 49ers ran for a whopping 174 yards. Unfortunately for the 49ers, Jake Tonges injured his MCL while falling and trying to leg-whip Myles Garrett. That could have been a penalty as well. Not a smart play.

OFFENSIVE LINEMEN: A

They gave up zero sacks and helped pave the way for 174 yards on the ground (5.9 per carry). Granted, they were facing a defense that was practically comatose, but still, the 49ers handled business against a defensive line that is dominant on paper.

DEFENSIVE LINEMEN: C

They gave up 5.1 yards per carry and never sacked Matthew Stafford. When the Rams committed to running the ball, the 49ers couldn't stop them. Fortunately for the 49ers, the Rams fell behind and had to abandon the run. And even though the 49ers couldn't put a ton of pressure on Stafford, they made him nervous, which affected his play.

LINEBACKERS: B-PLUS

Fred Warner was brilliant as always. He had 11 tackles and a forced fumble. Dre Greenlaw was solid -- six tackles. Hard to expect more from him at this stage of his career.

DEFENSIVE BACKS: A

Renardo Green shut down Davante Adams (not for the first time) and recorded just his third interception since high school. His confidence is surging. As is safety Marques Sigle's confidence. He's always among the first defenders to arrive at the ball. Today, he recorded nine tackles, which is impressive. Collectively, this group gave up a passer rating of just 61.2 despite playing behind a modest pass rush and a shaky run defense. Who would have thought that the secondary would be the best position group on the defense today?

SPECIAL TEAMS: B

Deebo Samuel had a 45-yard kick return -- he really might be one of the best kick returners in the league. Unfortunately, Eddy Pineiro, who usually is automatic, missed a 52-yard field goal after making a 56-yarder. Cut him.

COACHES: A

First, let's praise defensive coordinator Raheem Morris. He didn't sell out to stop the Rams' running game. He conceded 5.1 yards per carry, which seemed risky, but he was making sure that Stafford wouldn't beat him. In fact, Morris owned Stafford, just like last season when Morris was the Falcons head coach and they beat the Rams in Week 17. Morris used to be the Rams' defensive coordinator, so he has faced Stafford countless times in practice and clearly has his number. What a hire for the 49ers.

Next, let's praise Kyle Shanahan. He made all the right calls on this trip. He was right to bring his players out to Australia more than a week before the game. He was right to stop calling passes for Kittle after giving him a chance to show he was ready. He was right to feature Evans. He was right to split carries between McCaffrey and Black. And he was right to hire Morris. As a result, the 49ers just destroyed the team that lots of people predicted to win the Super Bowl. Of course, this one game doesn't mean the 49ers will win the Super Bowl. Remember, they beat the Seahawks Week 1 last season, and then the Seahawks went on to win the Super Bowl. But that Week 1 win was fluky and close. This one was decisive and embarrassing for the Rams. They deserved every bit of the humiliation the 49ers gave them. They cheated the process of preparation and disrespected the 49ers and Australia by showing up yesterday. Enjoy that long flight home tonight. The 49ers sure will.