Sri Lanka lost six wickets for 20 runs inside of 45 minutes on day two of the test to see the Black Caps hold a 74-run lead after the first
innings.
Boult picked up the final four wickets by LBW, after two good Tim Southee catches aided in the early damage.
Boult finished with figures of 6-30 from 15 overs.
Angelo Matthews, who saw six of his partners depart on Thursday morning, top scored for Sri Lanka and was not out on 33.
Yesterday, Sri Lanka thought they had the rub of the green at Hagley Oval, but Tim Southee delivered a mighty Boxing Day counter-punch.
Southee smacked 68 with the bat and then backed it up by ripping through the Sri Lankan top order, with his dazzling display catapulting the Black Caps back into a test that started disastrously.
At stumps on day one of the second test, Sri Lanka were at 88-4 in response to the Black Caps' 178 – by no means a hopeless position, but since the Black Caps had earlier slumped to 64-6, they would be thrilled with their response.
Absolutely nothing went right for the hosts early on. The grin plastered across Sri Lanka captain Dinesh Chandimal's face at the toss was the biggest indication, as he opted to bowl first on a wicket that was greener than the theoretical grass on the other side.
Three hours later, the Black Caps were reeling after one of best spells of Suranga Lakmal's career.
Lakmal's test bowling average – 39.98 - can be deceiving, with the veteran seamer usually having to toil away on spinning sub-continent tracks. He would have wanted to chop the Hagley pitch up and take it home with him, such was his opening spell, bowling for a remarkable 16 consecutive overs, taking the first four wickets to fall, and leaving the hosts in disarray.
Jeet Raval played a poor stroke and got a leading edge, Tom Latham got stuck in the crease and edged a full delivery to second slip, Kane Williamson tickled an edge through to the keeper from a back-of-the-length ball, and Henry Nicholls was cleaned all ends up by a beauty which jagged back in off the seam.
Lakmal said he set himself the challenge of taking a five-wicket bag once he saw he'd be bowling in favourable conditions.
"That's what we talked about before the game - that like we give the spinners a chance in Sri Lanka, they also have to give us a chance in a place like this. If they can do it at home, we have to do the job away. The fast bowlers have to look to get 10. You can't do it by yourself though. Teammates and coaches have really helped, and I thank them. As soon as I got on to the ground today, I told the coach that I'd be getting five in this game. I was able to do that."
