However, Irish-based Australian coach Williams was quick to criticise Ireland's display, nowhere near the level that saw Schmidt's side topple the All Blacks 16-9 previous year.
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.
With Scotland back in the game at 10-12, the second half was delicately poised and both teams went into the dressing room still on optimistic of a win.
"It worked out well for Ireland and it probably affected Scotland a little bit, but I think regardless of whether Hoggy is on the pitch or not Ireland were going to win".More news: Kate Middleton’s BAFTAs outfit included a sweet tribute to Diana
"We got a lot of our attacking game into play as well as really good decisions, really good work-rate off the ball, which meant we were finding space and the first half". 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.
"We are relying on others, but when it comes to next week [in Italy a week on Sunday] and the final two rounds we don't have to rely on them for how we approach things and how we perform", Schmidt said. It's not anger, it's 'Why did we have such a good first half and then we didn't play the same way in the second?
"It was an improvement after England but we can still play better", said the Ireland captain, Rory Best.
The Scots were penalised at the scrum, fumbled on possession and a Russell forward pass all gave Ireland easy outs from their territory but when the champions got into the Scots 22, they looked set to take the game away. Obviously, it wouldn't have done much for his confidence [conceding the try to Scotland] but to bounce back like that showed great resilience.More news: USA warships again challenge Beijing's claims in South China Sea
"But we don't strive for all right, we want to be the best we can be and England wasn't it".
Scotland's next match is against France in Paris in two weekends' time.
His coach Gregor Townsend took responsibility, saying Scotland had to improve their set-pieces. 'We'll see what will happen over the next few days. But if we hadn't won here, we were definitely out of it.More news: South Korea signs deal to pay more for USA troops