SANTA CLARA, Calif. (AP)Since Brock Purdy took over at quarterback for San Francisco late last season, no team in the NFL has scored more points, won more games or passed more efficiently.

While plenty of credit should go to coach Kyle Shanahan’s innovative play-calling and a bevy of playmakers led by Christian McCaffrey, Brandon Aiyuk, Deebo Samuel and George Kittle, the Niners reject the notion that the quarterback is just along for the ride as a creation of the system.

“That’s pretty ridiculous,” coach Kyle Shanahan said. “You’ve just got to watch the tape. He plays at a high level every time he is been out there. He’s done it in a lot of different situations versus a lot of different defenses, on the road, at home, playoff games, when injured. You can’t do all that stuff, he’s been out there too long. It’s on tape.”

The Niners have won all 10 regular-season games since Purdy replaced an injured Jimmy Garoppolo early in a Week 13 victory last season.

They are scoring 32.6 points per game in that stretch, with Purdy leading the NFL in passer rating (113.3) and ranking second in yards per attempt (8.5), while producing 21 touchdowns passing and rushing and turning the ball over only four times.

“From what I see, he is exactly what we need him to be,” All-Pro left tackle Trent Williams said. “He is exactly who we thought he was. He just continues to move forward, even-keeled.”

Purdy has done everything the Niners have asked of him, from extending plays with his athleticism, getting the ball downfield when needed and earning the trust of Shanahan, who has been more aggressive in end of half and fourth-down decisions since Purdy took over.

Just last week, Shanahan went for it on fourth-and-4 on the second drive of the game and Purdy delivered with a completion to Kittle.

“He’s got an aggressive mindset, he trusts in this team, we’ve got guys that have played a lot of football, and so we sort of expect it,” Purdy said. “It goes both ways. Players have to trust him, he trusts in us. We’re very thankful for that and we want to continue to have that relationship moving forward.”

About the only thing Purdy hasn’t done is lead the team from behind – and that’s only because the Niners haven’t really been in that situation.

In the 13 games in the regular season and playoffs since Purdy took over, the 49ers have rarely trailed in the second half. Purdy has thrown just 16 passes in those games when behind after halftime with 11 coming in a Week 17 win against the Raiders last season, three in a wild-card win over Seattle, and two while playing with a torn ligament in his throwing elbow in the NFC championship game loss at Philadelphia.

In fact, the only completion Purdy has thrown in the fourth quarter when trailing in that span came with the injured elbow on a 1-yard pass to Kittle against the Eagles.

He could be put in that kind of situation again on Sunday night when the Niners (4-0) get their toughest test of the season against Micah Parsons and the Dallas Cowboys (3-1).

The Cowboys held the Niners to just 19 points in a playoff loss last season for their lowest total in any game when Purdy was healthy. Purdy said it was the toughest test he has faced so far as a pro.

“They were a really good defense,” he said. “There was were times where just the pass rush or my rhythm, something just felt off in that game. They did a good job of just getting me off with some little things and just sort of maybe rushing things. I feel like I didn’t get in a good rhythm to process just what we had going on. So there were some some areas in there where I could definitely be better at.”

Dallas has been even stingier so far this season, allowing a league-low 10.3 points per game, while ranking tied for fifth with 14 sacks and tied for second with 10 takeaways.

They do much of their damage wen they get out ahead so staying out of those scenarios will be crucial this week.

“When you get into some bad situations and stuff, that the D-Line is tough to handle and they can make you make a lot of mistakes,” Shanahan said. “You’ve got to get rid of it quick sometimes, not always before you’re ready. … When you’re behind the chains and things like that, not just (last) Sunday, but really for the last three years they’re as good as team as any when they got you one dimensional and creating turnovers and getting after the quarterback.”

NOTES: OL Jon Feliciano (concussion) and RB Elijah Mitchell (knee) missed practice. … LB Dre Greenlaw (ankle), WR Jauan Jennings (shin), WR Deebo Samuel (ribs, knee) and CB Charvarius Ward (heel) were limited.