The San Francisco 49ers got a much-needed win on Sunday night ahead of their bye week, defeating the Dallas Cowboys 30-24 to sit at 4-4 at halftime.

It was an eventful night as the 49ers started slowly and Dallas led 10-6 at halftime. A 21-point third quarter led the way, however, as San Francisco staved off a last-ditch comeback for the win.

But on the way to earning the hard-fought victory, the 49ers again faced adversity, dealing with some injury issues as running back Jordan Mason was unavailable after some rush attempts in the early game.

Mason, who was dealing with a shoulder injury early in the week, didn’t play the entire second half, giving rookie fourth-round pick Isaac Guerendo a leadership role in a key situation.

Guerendo started the year slowly, dealing with multiple injuries, and hadn’t really seen big volume until San Francisco’s Week 6 performance against the Seattle Seahawks, when he finished the game with a 76-yard rush.

But on Sunday, Guerendo saw his biggest role yet, rushing for 85 yards and a touchdown on 14 attempts, taking over the lead in the second half as San Francisco went on a big scoring drive.

How did the rookie approach the opportunity for the 49ers?

“I thought he did a great job,” head coach Kyle Shanahan said of Guerendo. “He came in, he was ready to go. JP got hit, JP tried to come back and he might have, but Isaac rolled and did well.

“I think he’s learned from every run he’s made. There were a few runs earlier this year where he did well, but we judge him pretty harshly, everyone pretty harshly. And he had a couple of four-yard runs where we thought he could have gone seven yards. We’re tackling him pretty hard. And then you see how he puts that into practice and everything that we really pushed him with. He is very coachable, he is not a sensitive guy, he is very detailed and he is very ready for a newcomer. Things aren’t too big for him and he hasn’t had much in the preseason, but once he got healthy there and throughout the year, I feel like he’s gotten better every week.

Even after the win, the running back was focused on the areas that could be improved, which resonated with the coaching staff.

“There is always room for improvement,” Guerendo said. “Being able to revisit this and fix those little things – all those little details. We have a great (running back) room. It was really important for me to be able to ask any of those guys questions because obviously I was the rookie in the room. I am grateful for them, grateful for my coach and I appreciate them all.”

Quarterback Brock Purdy praised his running back and pointed to his learning attitude as a major reason for his rise up the depth chart.

“Yes, very happy for him,” Purdy said of Guerendo. “The way he comes to work every day and everything, and the chip he has on his shoulder, humble guy. He always asks questions and wants to make sure he does everything right. So if he does what he’s doing now for our team, I couldn’t be happier for him. And I understand, man, as a rookie coming in with some guys from the team and some big names in the group and stuff, you can be a little bit impressed in a way, but he comes in, it doesn’t matter to him out. He takes the ball and runs hard, so I appreciate that about him.”

San Francisco heads into the bye week with a chance to regroup across the board, as running back Christian McCaffrey could return for the first time this season.

But they needed Guerendo to get the win on Sunday night, and the rookie came off the bench well.