The Scottish Premiership's bottom side fought back from behind to claim a share of the spoils in Paisley and bring to an end a losing streak stretching back five games.
Next up is a massive challenge against Terry Butcher's Hibs side at Easter Road, with Hearts aiming to kick off 2014 with a much-needed win.
And Locke had no complaints about the response from his players as Hearts bounced back quickly from a crushing 4-0 defeat against Kilmarnock with a positive performance against Saints.
He said: "After the Boxing Day game it was one of two times this season that I've been deeply disappointed.
"I had a few choice words after that game and I asked for a response. I felt, in the second half especially, we got that in abundance today.
"We've got to try to take that type of performance into the games coming up.
"It's another tough game coming up but, if we play the way we did in the second half, we will give ourselves a great chance of winning the game."
Locke admits he feared the worst when Steven Thompson fired Saints into the lead less than two minutes into the match.
He said: "It was a poor goal. We had a couple of chances to clear it and we didn't and Thompson scored.
"But I thought we reacted in the right manner and we got ourselves back in the game.
"There wasn't a lot in the first half but we were dominant in the second half and very unlucky not to get three points."
Hearts claimed a point thanks to a superb volley from Jamie Hamill, who impressed for most of the game.
Locke added: "It was a fantastic goal and it summed up his performance for me.
"He got back to doing what he was doing earlier in the season.
"He covered every blade of grass, he passed it well, he won tackles. In that kind of form, he was a big asset for us."
Saints boss Danny Lennon - who revealed that Marc McAusland's half-time withdrawal was due to a migraine - felt a loss of focus after the break from his players cost them the win.
He said: "It was a terrific start for us. We kept the momentum going and we created good opportunities.
"The only thing we didn't have in the first half was another goal.
"We warned them at half-time that Hearts would come here and fight for every single point.
"That showed in their five yellow cards compared to none for us.
"I'm in no way saying it was a dirty game; it just showed how committed they are to fighting for every point.
"I thought we could have had a stonewall penalty but I felt at times some of the players lost that focus.
"It's a game where two valuable points have been dropped in terms of where we want to be."
Goalkeeper Marian Kello came to the rescue for Saints with a great save to deny Callum Paterson at the end.
Lennon added: "Marian's contract is up in January but we are very much under way with negotiations there so hopefully we will have a bit of closure on that in the next day or two. I'm quietly confident."