The Raiders are 2-8 in their road games under Jon Gruden. They have been outscored by 130 points in those games. 
Statistically, the Patriots have the best defense in the NFL. But considering the caliber of opponents the Patriots have played compared to the Bears, I would go with the Bears being the No. 1 defensive team. I can't see the Raiders putting up many points here even if the Bears are minus Roquan Smith and Akiem Hicks. Khalil Mack is sure to be fired-up playing against his former team. 
I actually like the Bears' offense more with Chase Daniel at QB instead of Mitch Trubisky. Daniel is the more polished, experienced and accurate passer. He doesn't have to do anything fancy just play with in his means for the Bears to roll past the Raiders. Minnesota buried the Raiders, 34-14, at home two weeks ago. The Bears just got done defeating the Vikings. 
This marks Oakland's third straight away contest. The game is being played in London, but time-wise it comes out to be a morning game for the Raiders. The Raiders are 1-6 SU and ATS the past seven times on the road during an early start time.