After surprising the basketball world by winning the first two games on the road against the No. 1 seeded Boston Celtics, the No. 8 seed Chicago Bulls have struggled to defend their home court.As the series heads to Game 5 in Boston, no home team has won a game yet, with the Celtics taking Games 3 and 4 in Chicago - the most recent victory coming on Sunday night.Following his team's second-straight loss, though, Bulls coach Fred Hoiberg was not happy with the referees, who he feels gave preferential treatment to Boston point guard Isaiah Thomas.According to ESPN.com, Hoiberg said that he believes Thomas picks up his dribble and carries the ball every time he drives to the basket:"Let me say this, Isaiah Thomas is a hell of a player," Hoiberg began. "An unbelievable competitor - he's a warrior, everything he's going through right now. He had a hell of a game tonight. But when you're allowed to discontinue your dribble on every possession, he is impossible to guard. He's impossible to guard when you're able to put your hand underneath the ball and take two or three steps and put it back down. It's impossible to guard him in those situations."Thomas has proven to be impossible to guard for most of the season, though, and Game 4 was no different. The grieving Boston star - who is still dealing with the unexpected death of his little sister Chyna - finished the 104-95 victory with 33 points (to go with seven assists and four rebounds).But, by getting to the basket frequently, Thomas drew several fouls and got to the free-throw line 13 times. Hoiberg feels like Thomas is able to get to the rim so often because he picks up his dribble, which is supposed to be something officials look for, but (perhaps with his wallet in mind) stopped short of criticizing the referees even further:"That's a great question," Hoiberg said. "They talk about it every year. They talk about it every year, being a point of emphasis. It should be called. I've said all I'm going to say about it. I'm not going to talk about it anymore."If Hoiberg is upset about Thomas getting to the free-throw line so often, it'd be interesting to hear what Celtics coach Brad Stevens has to say about how Chicago star Jimmy Butler was officiated on Sunday night, as Butler shot 23 free throws (making 19) while the entire Boston team made only 22 trips to the charity stripe.

Thomas had a response to Hoiberg's criticism, playing it cool during his press conference after the big victory:

Butler also finished with 33 points, but it wasn't enough to lead the Bulls to a home victory. Now, Chicago must head back to Boston and win in order to avoid falling into a 3-2 hole in the first-round series.

With Thomas rounding back into his All-Star form after his sister's shocking death, pairing him with the Boston crowd that loves and supports him so much may be too much for the Bulls to overcome in Game 5.