When these two teams had met earlier in the season, it was the White Sox not the Red Sox, that walked out of Fenway confident. Ozzie's crew had embarassed what was a Red Sox team that was starting to find their groove, and sweeping them. 

Since then these two teams have gone in opposite directions, The Red Sox have the best record in the league at 64-39. While the White Sox have hit a downward spiral and are now sitting below .500 at 51-52. 

It seems that White Sox manager is starting to lose his team. Which has been filled with promise, but are resulting with busts. Adam Dunn being the most notable of this. Dunn has been putrid. Hitting .163 for the White Sox since signing that big money contract. Alex Rios has put on another disappearing act. Their pitching hasn't been great either, if it's not their starters, it's their bullpen that's been imploding. 

On the other side of the coin, the Red Sox have come in with one of the strongest lineups in the bigs and only look like they are getting stronger. Though, hiccuping against Kansas City and splitting the series. After things like this the Red Sox respond in huge ways, typically by blowing opposing teams pitching off the mound. Their rotation, though battered and bruised; has maintained to be stable. The bullpen still remains to be a question, and it has looked like there's some stability coming out of there as well with reliever Alfredo Aceves being called upon to get key outs in big innings and has pulled through for Manager Terry Francona. 

I don't believe the Sox have a "revenge" mindset coming into US Cellular Field, just a one game at a time mentality that has been executed so well throughout the season. That's what they need to do to get through a struggling White Sox team and keep the lead in the AL East.