Select the most appropriate verb / verb phrase to fill in the blank.

The team .............................. the championship before their star player got injured.

To determine the most appropriate verb form to fill in the blank, we need to analyze the timeline and sequence of the actions described in the sentence.

The sentence contains two actions in the past:
1. The team winning the championship (indicated by the blank).
2. The star player getting injured ("before their star player got injured").

The clause "before their star player got injured" uses the simple past tense ("got injured"). The conjunction "before" indicates that the team's victory happened prior to this past event. When we want to express an action that was completed before another action in the past, we use the past perfect tense.

The past perfect tense is formed using had + the past participle of the verb (won). Thus, the correct verb phrase is "had won".

Let's evaluate the options:
• "has won" is in the present perfect tense, which does not fit a past timeline established by "got injured".
• "was won" is a passive voice construction and is grammatically incorrect in this context since the subject "The team" is the active doer of the action.
• "win" is in the simple present tense, which does not match the past timeline.
• "had won" is in the past perfect tense, correctly showing that the championship was won before the injury occurred.

Therefore, the correct sentence is:
"The team had won the championship before their star player got injured."