In such situations, attempting to sabotage the other person is highly unethical because even if it leads to success for you, another person has been wronged because of it.

For example, suppose one candidate locks the waiting room door behind them while they wait for their job interview so that the other contestant cannot get in and misses out on their opportunity. In that case, this kind of behavior only serves to bring down other people while also putting them at an unfair disadvantage.
Similarly, when playing sports, intentionally stealing somebody’s equipment or putting a physical barrier between them and victory would also constitute sabotage. Unless these are stipulated as parts of the game rules, this kind of act is entirely unjustifiable and, therefore, ethically unacceptable.

More info: What is WAN Optimization