Playing with a lighter load on her shoulders after winning the French Open title last month, Halep rolled back her arms and let the winners fly off her racket strings.
"I was relaxed when I came here. I didn't push myself. I didn't put pressure on myself. I felt ready today," Halep said with a smile after winning her first match as a major champion.
"I have expectations for myself, but not with the result. I feel ready to fight."
The Romanian world number one was broken once in the opening set and also faced two break points at 2-1 up in the second.
A forehand winner and a Nara error allowed Halep to sidestep that pothole and she wrapped up victory when Nara smacked a forehand long.
Like French Open men's champion Rafael Nadal, Halep opted to rest her aching limbs following her win over Sloane Stephens in the Roland Garros final.
She turned up at Wimbledon without playing any competitive matches on grass and the gamble did not harm her gameplan on Tuesday.
"I was a little bit worried because I didn't have a match on grass (before coming here)," added the 26-year-old who is bidding to improve on her 2014 semi-final appearance in London.
"But I was thinking that I had played many matches during the claycourt season. So I was kind of ready."
Many of her fellow top-eight seeds, however, were not ready for the challenge. By day two of the championships, four of them had departed.
Fourth seed Stephens and fifth seed Elina Svitolina failed to survive the opening day while Petra Kvitova, the winner here in 2011 and 2014, and France's Caroline Garcia checked out on Tuesday.
"Here on grass, you don't know what to expect," summed up Halep, who will next face China's Zheng Saisai.
(Reporting by Pritha Sarkar, editing by Clare Fallon)
