Had to declare early to force a result - McCullum
Brendon McCullum described New Zealand's victory in the first Test in Dunedin as "bloody hard work", on a surface that flattened out after the second day. The hosts were kept in the field for more than 212 overs, before they completed the 122-run victory mid-way through the fifth day.
All four New Zealand seamers had heavy workloads in this Test, as the team opted to rely on the left-arm spin of allrounder Mitchell Santner over offspinner Mark Craig. Tim Southee delivered 48 overs across the five days, while Neil Wagner and Doug Bracewell bowled 42 and 40.5 overs respectively.
McCullum said New Zealand's quick scoring rate in their own innings, and a declaration early on day four had both helped give the hosts time to achieve victory. New Zealand scored at more than four runs an over in each of their innings, and had declared at 404 runs ahead with little over five sessions of the match remaining.
"We knew 20 wickets was going to be tough especially when we didn't have the best of the bowling conditions," he said. "I think day one was the best of the conditions for the seam or swing bowlers - that was why we tried to maintain our scoring on rate on day, one because we knew we were going to have to buy some time later on.
"Also the declaration looks a reasonably aggressive declaration, but for us it was really the only way we were going to allow ourselves enough time to not just win the game, but also relieve the pressure of having to win the game. I think sometimes if you don't leave yourself enough time, then you start chasing wickets and that can lead to not getting wickets that you should.
"If Sri Lanka were good enough to chase 400 and run us down in the time that they had then, fair play to them then. We can handle losing if someone else is able to go out and play as well as what they would have had to. But in the end I was pretty comfortable."
Heading into the final day, Sri Lanka had Angelo Mathews and Dinesh Chandimal - their two most experienced batsmen - at the crease. They put on 56 together in the morning session, but were dismissed within three overs of each other.
"The Sri Lankans are a bloody tough opposition to get results against," McCullum said. "Angelo and Chandimal are two world-class batters, and we knew that they were going to be key today. We knew we had to spend some resource to keep them out. There were concerns because the wicket was so flat today. They're going to pose another tough challenge for us in Hamilton.
"Sri Lanka have got some excellent young bowlers who I think asked some questions on day one, as well. We're just thankful that we were good enough at the top of the order to withstand those pressures, and apply some pressure back on them."
McCullum also equalled Adam Gilchrist's world record for most Test sixes, when he launched Rangana Herath over cow corner in his second innings 17 not out. McCullum said that while it would have been nice to hit one more six in the innings to take the record all for himself, the team had decided they would declare when the lead passed 400. That shot had taken it to 404.
"I was hoping someone would ask me about the 100 sixes," he said. "It's the only record I actually care about. It's the only record that Kane Williamson or Ross Taylor aren't going to break as well, so I should be able to hold on to that one. I've been aware of it for a while, as you can probably tell by the way I bat all through my career."
Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @andrewffernando