Harrington added a 67 to his opening 78 at Torrey Pines
Padraig Harrington surged back into US Open contention after firing a stunning 67 to better his first round by 11 shots at Torrey Pines.
The Open champion was in danger of missing the cut but climbed back to three over - six off the lead but well-placed to mount a challenge.
"I played nicely but probably not as good as yesterday in terms of ball striking," said Harrington.
"But I made putts that missed yesterday and my bads shots weren't that bad."
The Irishman added: "Another two of those on the weekend should do nicely."
Harrington, who is hungry to add a second major to his collection, admitted that his focus had turned to just making the cut after his opening seven-over 78 but he stressed he did not do too much differently on Friday.
I was aiming for 69 but 67 is a nice return
"Yesterday was very difficult on the greens in the afternoon. They dried up and the sun was out and they were only going one way from there," said the Dubliner, who tied for fifth at the Masters and is coming off a fourth at the St Jude Championship last week.
"It was putting a lot of pressure on the rest of my game, every time I hit a slightly off shot I was making at least a bogey.
"Today, I still made four birdies, like yesterday, but just holed the odd par putt here and there. When you are doing that, it makes it so much easier to hit your shots into the greens.
"You are so much more accepting of the odd bad shot you hit when you are holing the putts and that was what I did today.
"I knew I made four birdies yesterday and I knew if I could make four more today and keep the rest of it tidy, I'd have a good score.
"I was aiming for 69 but 67 is a nice return, it even felt like it might have been one or two better than that."