Ireland coach Joe Schmidt praised his team's set-pieces and ferocious defense, but said the key difference from the week before was their attitude.
World player of the year Sexton lasted only 24 minutes, after suffering a stamp on the ankle and a head injury, as Ireland bounced back from their opening weekend home loss to England with a 22-13 victory against Scotland at Murrayfield.
The 33-year-old failed a Head Injury Assessment (HIA) and Joey Carbery came on, stepping up to set Keith Earls free for the winning score.
Ireland fly-half Johnny Sexton was forced off after being struck by a series of big hits, the heaviest in the build-up to their second try.
"But he's pretty good now".
The Scots appeared to have pushed the Irish back in midfield and the ball went loose, but Carbery picked up and slipped through a gap as Allan dell and replacement Rob Harley missed a double tackle.
"If we were able to replicate that first half after the break, then I think we'd be here with a win".
"It was a little bit cumulative really". 'With the game going the way it was going, you can understand why we got frustrated. You can see the graze down his leg.
"From a self-preservation perspective, he doesn't have to get back into the pocket". They were also architects of their own downfall at times, with Tommy Seymour and Sean Maitland's mix-up gifting Ireland scrum-half Conor Murray the opening try on the 10-minute mark.
"There was definitely a rise in temperature, definitely a rise in energy, from last week", Schmidt said. We're going to give it all we've got to finish as high as we can. We're relying on other people now.
Scotland have maintained their third position in the table with a win and a defeat apiece and will line up against France in round three at Stade de France in Paris on 23rd February.
Centre Huw Jones and fullback Stuart Hogg suffered knee and shoulder ligament injuries respectively in the same game, the SRU added, but both remain part of the squad and will be assessed by a specialist this week. The Scotland head coach, Gregor Townsend, felt his side should have been awarded a penalty but does not expect the citing officer to review the incident.