Whoa, was that a Super Bowl level pass rush?

In Matthew Stafford’s last setback in the first half on Sunday, the Rams quarterback was sacked in 3rd and 1st place by 49ers defensive tackle Arik Armstead and defensive end Nick Bosa.

It was a big room. This allowed the 49ers to reclaim the ball before half-time and score a basket to reduce their deficit to 17-3.

On Stafford’s last settlement drop, at the Rams’ first base off the 37-yard line with 21 seconds left, he was sacked by Armstead.

It was a huge game. It kept the Rams from getting in position to hit a potential winning basket and sent the game into overtime.

On Stafford’s latest game? He was pierced by Bosa as he threw a deep pass down the right sideline, and he watched from the turf as cornerback Ambry Thomas took him off.

It was a monumental piece. He sealed a 27-24 overtime win over the Rams and sent the 49ers to the playoffs as the No.6 seed who will visit the Cowboys in a wildcard game on Sunday.

There was, of course, a bevy of the bonkers 17 point comeback victory heroes. However, one neglected area – and perhaps the main reason for the optimism about the arrival of a Super Bowl – was the pass rush after halftime that set the mood for 2019.

Two years ago, the 49ers were led to the Super Bowl by a withered defensive front that knocked out quarterbacks and resumed games. In 2021, they had a solid unit, tied for fifth in the NFL in sacks (48), but nothing worthy of a Gold Rush-ian moniker.

Until the last 38 minutes on Sunday.

The 49ers tied a season-high with five sacks, and their pass rush was the reason the Rams’ offense went from unstoppable (17 points on the first three drives) to invisible (seven points on the last eight discs).

Consider: Stafford completed 15 of 16 passes for 153 yards with two touchdowns in the first two quarters. Based on a video review, he was hit by a defender in just three of his 18 first-half dropouts, with two hits via sacks.

In the second half and in overtime: Stafford was hit on 11 of his 19 drop-backs, which is why he completed 6 of 16 passes for 85 yards with two interceptions and a touchdown.

Stafford paid a price for even his best shot in the second half. He was hit by defensive lineman Arden Key on a perfectly placed 30-yard lob to wide receiver Cooper Kupp in the fourth quarter.

By the end of the game, Stafford was limping from a toe injury, and red scuffs were prominent on his left arm when he was in midfield for the overtime draw.

The 49ers might need to replicate that pass rush to beat the Cowboys, who, like the Rams, have a top 10 offense led by a 4,000-yard QB (Dak Prescott) and two high-end wide receivers ( CeeDee Lamb, Amari Cooper).

The 49ers might do it as their passing rush has become multidimensional. The recipe for slowing down the defensive front for most of the season was simple: just pass Bosa, who has managed 14 of his 33 sacks (42.4%) in his first 13 games.

In the last four games, however, Bosa has only gotten 1.5 of his 15 sacks (10%) as linemen such as Armstead, Key and Samson Ebukam have become more effective.

Ask Stafford.

Other observations of the victory over the Rams:

• The 49ers chased Stafford mostly in winning head-to-head clashes, but defensive coordinator DeMeco Ryans effectively created the pressure at two key points in the second half.

The first situation: The 49ers were leading 17-10 midway through the third quarter, and the Rams had a 3rd and 6 in their 29th.

Ryans sent free goaltender Jimmie Ward and inside linebacker Dre Greenlaw through the same area on the left side of the Rams’ offensive line. Sony running back Michel recovered Ward, but no one touched Greenlaw, who blasted Stafford and forced a check.

The second situation: The game was tied 17-17, and the Rams faced the 3rd and 10th in their 42nd with about 13 minutes left in regulation.

Ryans had lined up inside linebacker Fred Warner as a defensive tackle standing on the left side, next to Bosa. and overloaded the right side with Armstead, Key, and Ebukam. Those three linemen gave in on the left side of the offensive line, Warner beat right guard Austin Corbett, and Warner and Key combined on a 10-yard sack.

• Three days before kick-off, tight end George Kittle suggested the Rams might be intimidated when asked about the 49ers’ winning streak against rivals NFC West, then five games away. .

“Whenever we face them we try to come out and be as physical as possible,” Kittle said.

And it was visible on their 74-yard tying touchdown in the third quarter. Not only did this 11-game walk start with 10 straight points, nine of them were between tackles, in the teeth of the Rams defense.

The tone was set by running back Elijah Mitchell in the first game of the drive. Mitchell was encountered at the line during his run, but he broke tackles from linemen Greg Gaines (312 pounds) and A’Shawn Robinson (330) before rolling safety Jordan Fuller, who was credited with the tackle at the end of Mitchell’s 7-yard statement.

• Did quarterback Jimmy Garoppolo complete 43 yards through wide receiver Deebo Samuel on the tying TD who started with 87 seconds left in regulation? It was his best shot, given the degree of difficulty and the high stakes.

But the runner-up was a throw that I didn’t appreciate until a second viewing.

The 49ers were down 17-3, had just kicked off the second half and were quickly faced with a 3rd and 3 to their own 32s.

Garoppolo, on a shotgun, came under pressure from All-Pro defensive tackle Aaron Donald shortly after taking the snap. However, Garoppolo waited for a beat for running back JaMycal Hasty to break free on a short road down the middle and deliver the pass as he was crushed by Donald. (Fox’s Joe Buck: “Garoppolo kinda hangs on …”)

The result: a first down for 13 yards and a touchdown four plays later. Play.

• Stafford was called up for a false start before the second snap of the Rams game because of the crowd noise… at SoFi Stadium.

As someone who spent much of their childhood in Southern California, I am qualified to say that the Red Sea stands were yet another black eye for sports fans in the area.

I guess the Rams fans – I’ve heard of it – are going in inning five as well.

Eric Branch covers the 49ers for The San Francisco Chronicle. Email: [email protected] Twitter: @Eric_Branch