You've confused yourself by cutting off the beginning of the sentence. He lists three factors that contributed to this being the second-biggest week for the XBox brand in the US. "Worldwide Xbox Black Friday sales in the Xbox Store broke records with an increase of 57 percent across Xbox One and Xbox 360, global Xbox Live Gold subscriptions were up over 40 percent, and U.S. Xbox One console sales at retail were up 22 percent over the same period last year, making it the second biggest Black Friday week in 15 years of Xbox history in the U.S." See how it's all one sentence? A, B, and C, caused D.
"Concession sales were up 60%, season ticket sales were up 23%, and sales of sunglasses doubled, making this the biggest opening day in Six Flags history!" They didn't say sunglasses just became their best-selling souvenir of all time; they said the revenue from the increased sunglasses sales helped them break the previous revenue record, along with the sodas and season tickets.
"making [last week] the second biggest Black Friday week in 15 years of Xbox history in the U.S." That was the result; #2 week ever in the US. Three causes; lots of revenue from the XBox Store, lots of revenue from Gold, and lots of Bone sales in the US. It's clear that all three factors contributed revenue, and that revenue is what's being used to gauge the "size" of the week. Not unit sales of a particular console. The increase in unit sales caused an increase in revenue, which, when combined with the increased revenue from the other two sources, gave them their second-highest grossing Black Friday Week, in the US. Presumably worldwide, their revenues for the week were third-best or worse.