Learn Russian: Твоё главное достижение в том, что ты сумел сохранить команду. - Your main achievement is that you managed to save the team.

The verb суметь (to manage to / to succeed in) is a verb of success. When you successfully manage to do something, the result is achieved. In Russian, verbs of success, achievement, or forgetting are always followed by a perfective infinitive to emphasize that completed result.

Why does the sentence say в том, что instead of just что for "is that"?

In English, we often say "Your achievement IS THAT you...". Russian doesn't use a "to be" verb here. Instead, it uses a pointer phrase: в том, что (literally "in that, what"). It links the noun достижение (achievement) to the action. Think of it as "Your achievement consists IN THE FACT THAT you...".

Could I use смог instead of сумел here?

Yes, they are very similar. Смог (from смочь) is the general word for "was able to." However, сумел (from суметь) specifically implies you had the skill, know-how, or resourcefulness to manage a difficult situation. It is a perfect fit for describing a great достижение (achievement).

Does сохранить mean "to save" like saving someone's life?