他球路多变，令对手防不胜防。

His opponent couldn't stand up to his varied and fast-changing tactics.

遇到这样的对手几乎防不胜防。

Defence was well-nigh impossible against such opponents.

由于梢子头比较短小，灵活性很大，所以击打力也非常强大，往往令对手防不胜防。

Because the Shaozi is quite short and small, it is agile and has strong force of punching, thus it usually makes the opponent impossible to defend effectively.

除了放松一下身心，我发现自己还在琢磨今年这个兔年是会风平浪静、尽在掌握，还是意外频生，防不胜防？

While enjoying the holiday and relaxing, I found myself wondering whether this Rabbit Year will be one of those relatively even-paced, predictable ones, or one which brings big, bold surprises.

但另一方面，我们也要看到，在这个世界上如果有套戥机会，总会有人去做套戥的行为，而且几乎是防不胜防的。

But on the other hand we should also see that when there is the arbitrage opportunity in the world, there are always people seeking it and it is hard to guard against.