Paul Pierce and the Celtics hit the wall a bit after playing eight games in 12 days.

AP photo / Winslow Townson

WALTHAM, Mass. — Boston coach Doc Rivers expects the Celtics to play a lot better against the Utah Jazz on Wednesday night at TD Garden than they have performed over their last three games.

That’s because the Celtics used Monday and Tuesday to get in some practice time to clean up some sloppiness and fine-tune their plays. They also got in some much-needed rest.

The Celtics had to play eight games in 12 nights to start the season, and because of that, they hadn’t been practicing a lot and were fatigued toward the end of that stretch.

“It’s been good for us to get back to practice and refine some things and get back into the flow,” Boston captain Paul Pierce said. “We played a difficult schedule — eight games in 12 nights. We got a little bit of rest and really fine-tuned a number of things that we struggled in the last three games so we can take care of business here at home.”

“We had an eight-in-12 stretch and we needed these couple of days to get our stuff back together and get back to playing Celtic basketball,” forward Rasheed Wallace said.

The Celtics went 7-1 during their difficult stretch, but struggled over the last three games offensively and defensively.

“Defensively we had some slippage,” Pierce said. “We allowed teams to shoot 50 percent and score over 100 points, and that’s something that the Boston Celtics just don’t do. We are a defensive-minded group, so it’s all about getting back to [our foundation].”

The Celtics began to show some wear and tear against Minnesota. The Timberwolves (1-7) are one of the worst teams in the West, but it us understandable that the Celtics did not play well against them after traveling more than 1,100 miles to face them one night after they beat the 76ers in Philadelphia.

Boston allowed Minnesota to knock down 52 percent of its shots in a two-point Celtics’ win.

The Celts then had to travel nearly 1,400 miles back across the country to battle the Suns, who handed the Celtics their first loss of the season. Rivers said that the Celtics “did not have a lot left in the tank” when they had to play the injury-plagued New Jersey Nets less than 24 hours later. But the Celtics were able to beat the winless Nets, 86-76.

“It’s hard to be disappointed with 7-1,” Boston guard Ray Allen said. “Obviously we’d like to be 8-0 right now. ... We still look back at that Phoenix game that we lost and we all feel like we could be in better shape. We felt like, offensively, we could have executed better. We just had some miscues, so all of that stuff, we talked about what could have been better and that’s what we focused on.”

Rested and refocused, the Celtics will host a Utah team Wednesday night that has experienced a lot of success against the Celtics in recent years, taking four of six meetings — including two of three in Boston — since the start of the 2006-07 season.

“They’re a good team,” Wallace said. “I think they have the talent to beat the Lakers, the talent to beat the Spurs. You can’t sleep on them. They have a good point guard. They have good big men, good swing men and a good coach. It’s definitely going to be a challenge for us.”

Utah, led by point guard Deron Williams (21.4 points, 10.7 assists), power forward Carlos Boozer (16.7 points, 11.6 rebounds) and center Mehmet Okur (15.3 points, 7.7 rebounds), has alternated wins and losses in its last four games, and is seeking its first consecutive victories since late last season.

“They’re a good team,” Rivers said. “Utah is solid. They have another great point guard in Deron Williams. Okur presents all kinds of problems. … He stands out at the 3-point line and drags your team out there and [Andrei] Kirilenko is still Kirilenko. He’s a disruptive force defensively.”

Rivers said that backup forward Brian Scalabrine (back spasms) likely won’t play any games this week, and that backup forward Bill Walker (knee), who returned to practice for the first time since training camp on Monday, has looked good.

Williams, meanwhile, injured his right calf against the New York Knicks on Monday and is questionable for the game.

No matter what happens against Utah, Rivers said that the Celtics need “to keep getting better. Obviously we love our start but we want to have a great finish, and to do that we just have to keep working.”

roblee@projo.com