To go head-to-head 意思是两人之间头对头地竞争。
They're both amazing swimmers - I can't wait to see them go head-to-head.
There can only be one winner. We'll have to go head-to-head to decide who it is.
还有一个意思类似的短语是 neck-and-neck, 它的意思是在竞争或竞赛中不相上下。
At this stage, either of them could win. It's neck-and-neck!
英语中还有很多类似结构的短语，比如 eye-to-eye, face-to-face, cheek-to-cheek, shoulder-to-shoulder 或 back-to-back 不过他们的意思各不相同!