The 8-2 defeat to Bayern Munich in August triggered changes at Camp Nou from top to bottom, with president Josep Maria Bartomeu, coach Quique Setien and several senior players no longer at the club.
Ronald Koeman and a number of young players have come in, but Barca are without a win in four league games having made their worst start to a season in 18 years.
"The club right now is how it is," Pique told reporters. "It's in a process of many changes, changes I think are necessary. We needed to turn things around. It was obvious that we were in decline and every year we were a little worse.
"We don't have much time, but we need it to improve. There's never a transition year at Barcelona, you're always obliged to win. Now we have elections and a new president and board will come in and we will see changes in the coming months little by little.
"In the meantime, we have to keep on competing, but it's not easy because of the circumstances. Not just relating to what's going on at the club, but because we're here with no fans as well.
"Things have gone well in the Champions League, but in La Liga we have to change and we're going to change. We have young players coming through, they have added dynamism to the group and to the way we play. We don't have much time but we need it to gain confidence and keep on growing."
A Lionel Messi penalty gave Barca a fifth-minute lead at Camp Nou against Kiev, who had nine players out with coronavirus, and Pique headed in their second goal in the second half.
Viktor Tsyhankov pulled one back for the away side with 15 minutes to go and but for the brilliance of goalkeeper Marc-Andre ter Stegen, the away side may have snatched a point.
"We started really well and could have scored two or three, but then we lost control of the game," Pique added. "There are things that we have to improve. In this case, I would say the pressing was not always good, not organised."
Barca coach Koeman agreed with Pique's analysis of the game.
"We were not good without the ball," Koeman said in a news conference. "For me, the problem is if you press, you must press as a team, if not you leave space. We must improve without the ball.
"In general, we have been OK in defence this season, but Kiev played well and created a lot of danger."
In the end, Barca were indebted to the returning Ter Stegen. The Germany international made a string of fine saves on his first appearance of the season following a knee problem.
"Once again he's shown he's a great goalkeeper," Koeman added. "He's only had one-week training but we have seen that he's in form and that's important for the team."