The 49ers and Lions will both be looking to shake-off their season-opening losses when they square-off this Sunday at Levi's Stadium.

San Francisco will also look to rid themselves of poor execution in the red zone which has evolved from a concern in 2017, to a full-blown issue in the early season.

Following last Sunday's 24-16 loss in Minnesota against the Vikings, Kyle Shanahan's 49ers returned to their team headquarters in Santa Clara scratching their heads over several missed opportunities, finishing with one touchdown inside the opponent's 20-yard line.

The Niners executed one touchdown in four trips to the red zone, but even that 22-yard scoring pass from Jimmy Garoppolo to Dante Pettis is only credited because their scoring drive took them inside the Minnesota 20-yard-line. But, a five-yard sack moved the 49ers outside the red zone before the touchdown pass.

It was Alfred Morris fumbling away the ball at the Vikings' one-yard line that marred the 49ers in the first half that set the table for costly turnovers and those missed opportunities. Garoppolo threw three interceptions en route to the loss.

"It's just the same for every other team in the NFL, it gets harder the tighter you get," said Shanahan on Monday in his coach's press conference. "It always does. That's every team.

"Last year, I think we got better in the red zone as the year went, just like I think we got better on offense as the year went. Usually, a really good offense will do better in the red zone because they're really good. I think we've made a lot of strides, but it definitely does get tougher down there."

The 49ers ranked 27th in the NFL in touchdown execution inside the red zone last season at 47 percent. But in the final three games of the season, during the Niners five-game winning-streak under Garoppolo, San Francisco's touchdown execution inside the red zone increased to 60 percent.

What cannot be ignored was that San Francisco was facing a stout Minnesota defense that last year ranked at the top defense in the NFL in yards and points allowed, and despite the four turnovers in their season debut against the Vikings, they were there in the end with opportunities to steal the game.

The player who shined the brightest in week one was DL DeForest Buckner, who totaled a career single-game high 2.5 sacks and seven tackles.

Rookie linebacker Fred Warner, filling in for the suspended Reuben Foster, also was among the biggest performances in the season opener as he tallied 12 tackles and forced a fumble from Minnesota's running back Dalvin Cook.

After losing top running back Jerick McKinnon for the season a week before the season opener, San Francisco sustained several new injuries coming out of Week one.

Wide receiver Marquise Goodwin is one of several listed as questionable for Sunday’s game against Detroit. Shanahan said Goodwin suffered a “deep thigh bruise” in Minnesota. Center Mike Person is listed as questionable with a foot strain, linebacker Brock Coyle is questionable after suffering a concussion and Joshua Garnett is questionable with a dislocated toe.

The Lions were up-ended 48-17 by the Jets in their season opener in Detroit last Monday. Running back LaGarrette Blount is listed as questionable for Sunday’s game against the 49ers after hyper-extending his left knee against the Jets. Defensive end Ezekiel Ansah did not play in the season-opening loss and is also listed as questionable for Sunday with a shoulder injury.

Detroit also lists offensive tackle Andrew Donnal and guard T.J. Lang as questionable for Sunday.

Sunday’s game will be the first of the season at Levi’s Stadium. Kickoff is scheduled for 1:05 p.m.

Follow Sean Cunningham on Twitter: @SeanCunningham