I'd say that "Gentleman" has a very strong chance of overtaking it for at least next week, but I think it could also return to #1 if no strong competition emerges.
It's going to be close. If PSY is pulling in 20m+ streams from the US for this week, it's his. He probably won't sell more than 100K copies (given his descent on iTunes lately), but this is one of those songs that have weekend benefits. We shall see.