It was a tough loss for the San Francisco 49ers in the midst of a tough season. They're now 3-4 after a Week 7 loss to the Kansas City Chiefs and they've lost two of their last three.

There is certainly no shame in losing to the defending back-to-back Super Bowl champions, but this one hurt for a couple of reasons.

First and foremost, this was the 49ers' opportunity to exact a bit of revenge for the Super Bowl LVIII loss to the Chiefs this past February. Let's not even get into Super Bowl LIV in 2019-20, which also saw the Chiefs beat San Francisco on the NFL's biggest stage. It's been an abysmal run for the 49ers as it relates to the Chiefs. San Francisco has lost the last five matchups against Kansas City. The 49ers' last win against the Chiefs was in 2014.

That's a tough stretch, but the toughest loss is always the last loss, which was a 28-18 affair that was as ugly as it was uninspiring for the 49ers.

These three players deserve the most blame.

49ers QB Brock Purdy looked awful against the Chiefs 

49ers head coach Kyle Shanahan has made quarterback Brock Purdy's life easy ever since “Mr. Irrelevant” was drafted with the 262nd overall pick in 2022. Purdy has been able to rely on Shanahan's running scheme, a combination of safety nets in Deebo Samuel, Christian McCaffrey, and George Kittle, and an always-strong defense to sometimes coast to wins.

It has been different this season, though. Sure, the 49ers are banged up and they miss McCaffrey more than they'd probably admit, but Purdy was asked to try to carry things a bit against the Chiefs and keep up with the Mahomes-led offense, and he failed miserably.

Purdy completed just 17-of-31 passes for 212 yards. He didn't throw a touchdown and he was picked off three times by the Chiefs. His 36.7 passer rating was the lowest of his career.

49ers quarterback Brock Purdy (13) stands on the field after the game against the Kansas City Chiefs at Levi's Stadium.
Cary Edmondson-Imagn Images

After the game, things were so bad that Shanahan reportedly had a long conversation with the 24-year old quarterback by his locker.

On Monday, Shanahan tried to downplay the situation.

“We were just talking like we always do, I just didn’t realize you guys were all standing behind me spying on us,” Shanahan said while laughing, according to NBC Sports Bay Area. “I love talking to guys after the game, I just happened to be walking back and he was just standing right there so we stopped and started talking.”

Shanahan made it sound routine, but it couldn't have been good considering the three turnovers. Purdy now has thrown seven interceptions to nine touchdowns.

The 49ers run defense deserves criticism

The 49ers have always had a solid defense, well, at least in the Shanahan era. And sure, Mahomes and Andy Reid were on the other sideline. Mahomes may be the best quarterback since Tom Brady and Reid is an offensive mastermind, so there's no shame in giving up yards or points to the Chiefs.

The 49ers still gave up too much on the ground to the Chiefs though. On a day in which Mahomes was largely bottled up as a passer — he competed just 16-of-27 passes with no touchdowns and two picks of his own —the Chiefs were able to do much of their damage on the ground.

The Chiefs ran for 184 yards as a team, which included 78 yards and two touchdowns from veteran running back Kareem Hunt. Mecole Hardman Jr. took a jet sweep to the house for another score on the ground also.

The 49ers shut down a hobbled Chiefs' passing attack and that's not even mentioning the fact that Travis Kelce was held to just four catches and 17 yards.

Had the 49ers only been able to slow down the Chiefs on the ground, they could have won.

The 49ers needed more from RB Jordan Mason

In a game in which Purdy was struggling and Samuel had to leave due to illness (which ended up being pneumonia), the 49ers needed everything they could get from their running game.

With McCaffrey gone for the season, the mantle of Shanahan's rushing attack has fallen onto third year undrafted running back Jordan Mason. For the most part, he's done his part. As it stands, he's the NFL's second leading rusher behind only Derrick Henry, which is good company. Mason has rushed 128 times for 667 yards and three touchdowns.

Unfortunately for the 49ers, only 58 of those yards came against the Chiefs, and Mason didn't find the end zone for the third straight game.

He'll need to step up even more, moving forward, for the 49ers.