SANTA CLARA -- On the 49ers' first snap of the day, Corey Liuget beat a one-on-one block by Jonathan Martin (who had lined up on the overloaded left side of the offensive line) to hit Frank Gore for no gain. It set the tone for the rest of the quarter as the Chargers defensive line, especially Liuget, dominated the vaunted left side of San Francisco's line. To wit:
* On 3rd & 12, Liuget helped run down Colin Kaepernick on a scramble. Safety Eric Weddle hit the quarterback from behind and he lost the ball.
* On 2nd & 9, Liuget slipped free of left guard Mike Iupati's block and then hit Kaepernick as he was throwing. The Chargers recovered the ball at the San Francisco 14.
* On 1st & 10 from their own goal line, the Chargers' Melvin Ingram bull-rushed Joe Staley and collapsed onto Kaepernick as he threw from the end zone. Kaepernick got rid of the ball in time to avoid a safety.
* On 1st & 10 in the second quarter, Dwight Freeney slipped past Iupati's block to tackle LaMichael James for a two-yard loss.
Two things: Whenever Iupati has struggled in the past, it's been because he over-commits, loses his balance going forward and can't recover in time. Iupati scholars will recall that Geno Atkins schooled Iupati in this way during the Senior Bowl in 2010. That was Iupati's main issue on Sunday he got too high, didn't move his feet and was not quick enough to recover.
Second: There was plenty of talk that yesterday's struggles were a clarion call for the 49ers to broach a deal with guard Alex Boone. Yes, the 49ers would be better off with Boone than without him. But, again, the issues were nearly all on the left side of the line, not the right side where Joe Looney was filling in for Boone and where Martin was playing for Anthony Davis. Both Looney and Martin had solid outings and Martin especially has made true strides in the last month.
Note to Iupati: Liuget and the Chargers will return to Levis Stadium on Dec. 20.
The second-team offensive line again had a solid game. It's not that any one player stands out, but that they play well as a unit. Hard-running Glenn Winston led all rushers with 58 yards and a 7.3-yard-per-carry average. He did most of his damage behind the right side of the line where Ryan Seymour was at guard and Michael Phillip at tackle.
On Winston's 27-yard touchdown run, left guard Al Netter pulled. He, Phillip and tight end Kevin Greene all had great blocks. Again, none of those guys physically dominated anyone but rather played good, technically sound football. That points to excellent coaching.
As far as Winston Not to get all man-crushy, but I've seen him without his shirt and he's looks like a Greek statue that lives in the weight room. He looks like Tarzan and runs like Tarzan. A very strong outing for him. Meanwhile, Jewel Hampton didn't get any carries on Sunday.
Ian Williams did not play a lot of snaps. But the 49ers' starting nose tackle looked good when he was on the field, and you certainly couldn't tell he was coming off a severe ankle injury.
Rookie cornerback Kenneth Acker had no flashy plays in coverage like last week, but he made three very good hits on either runs or after the catch. A solid game for him. The same could be said for starter Chris Culliver, who was solid in run support and who did a nice job breaking up a pass to the Chargers' No. 2 tight end on a long throw, Philip Rivers' only incompletion of the game.
Shayne Skov had another strong game at inside linebacker, his second straight. Again, I don't think he makes the 49ers' 53-man roster. Another team's 53-man squad? That's a better question. Seahawks GM John Schneider was on hand last week; Raiders GM Reggie McKenzie was in Santa Clara Sunday.
Some might say Michael Wilhoite struggled on Sunday. He's not NaVorro Bowman, which was evident on an outside run by Ryan Mathews that Wilhoite couldn't quite stop at the edge of the line of scrimmage and that Mathews turned up field for a 14-yard gain.
But no one is Bowman but Bowman. I thought Wilhoite had a solid outing, paired well with Patrick Willis and looked really good on the team's stand at the goal line.
When Craig Dahl was beaten by tight end Antonio Gates for a touchdown, it seemed like he was looking for underneath help from Willis in the same way he was looking for underneath help from Chris Borland last week on the touchdown by Denver tight end Julius Thomas.
Jim Harbaugh was 0-2 on challenges vs. San Diego. The team was 2-9 on challenges last year. That why the words, The 49ers are out of challenges were music to the ears yesterday.
Read Matt Barrows blogs and archives at www.sacbee.com/sf49ers.