"Clearly, for my team it'd be great to start off well," Nibali told Cycling Weekly. "The season is long, though, and some big goals ahead, the Giro.
"It's not easy. The Terminillo stage was also a chance to understand the team's workings. We'd never done work like that, that was the first time. Maybe we went too early when we led the race. Maybe that was the mistake.
"We need to understand the mechanisms and maybe we lack some condition."
Nibali switched from team Astana this off-season to begin and lead a new Middle Eastern WorldTour team, Bahrain-Merida. He helped launch it at Prince Nasser’s palace in January and began racing later that month.
He said that he is slightly overweight, around two kilograms, adding that he will have a chance to shed those kilos over the next month training, likely with an altitude camp on Spain's Tenerife island.
Between the Tirreno-Adriatico, which he won twice already in 2012 and 2013, and the Giro he will only race the Tour of Croatia, April 18 to 23.
The Giro d'Italia starts on May 5 with some of the strongest competitors in recent history, Quintana, Sky's Geraint Thomas and Mikel Landa, Fabio Aru (Astana), Steven Kruijswijk (LottoNL-Jumbo), and Adam and Simon Yates (Orica-Scott).
"I lack a bit of condition, for sure, maybe my legs need another race in them," he continued.
"In the end, yesterday, my feelings were good but just that I lack something. I need to improve on the climbs, for sure. This was the first summit finish I've done, but... I did recover well.
"I am going better day after day. Maybe it's my weight, but there's still a lot of road between here and the Giro."
Nibali won the 2013 and 2016 Giro already and can afford to laugh. He joked that at least with the extra two kilograms that he is warmer in the hills around central Italy.
Watch: Giro d'Italia essential guide
"For the Giro, I'm not worried, we are still one and a half months off to the start and almost two months to the end," his trainer, Paolo Slongo said.
"The Giro won’t be a problem, it's only here that he might have a better mood if he won something.
"We for sure have space to improve. He came to Tirreno-Adriatico in good condition, but not at his top this year with the Giro in mind. He's completive, with cycling as it is, though, he can't be at these races 100%.
"And for Bahrain, yeah, it'd be good to win, but that's the way it is. We can't do much. The Giro is the most important goal."
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