Baada ya mechi, kapteni alipokea medali mbele ya nyavu huku wenzake wakipiga makofi.

Yes. Baada ya means after before a noun phrase, and it is best learned as a set expression.

• baada ya mechi = after the match
• baada ya kazi = after work

Even though English just says after, Swahili uses baada ya.

Because in Swahili, a normal finite verb usually includes a subject marker even when the subject noun is also present.

So:

• kapteni alipokea = the captain received

Here a- means he/she, -li- marks past tense, and pokea is the verb root receive.

So alipokea breaks down as:

• a- = he/she
• -li- = past
• pokea = receive

Yes. Kapteni itself does not show gender, and the verb form a- can mean he or she depending on context.

So this sentence could mean:

• a male captain received the medal
• a female captain received the medal

You need context to know which one.

Because Swahili often uses animate/person agreement for nouns referring to people, even if the noun is a loanword or does not have the usual m-/wa- shape.

So:

• kapteni alipokea = the captain received

not

• kapteni ilipokea

Since kapteni refers to a person, Swahili treats it grammatically like a person for agreement.

Mbele ya means in front of.

So:

• mbele ya nyavu = in front of the net / in front of the goal net

This is another expression worth learning as a chunk:

• mbele ya nyumba = in front of the house
• mbele ya watu = in front of people

Nyavu means nets or netting, and in a sports context it often refers to the goal net or the net.

Its singular is wavu, but in sports you will often meet nyavu in expressions connected with scoring or being near the goal area.

Huku introduces a simultaneous or accompanying action. In this sentence, it means something like:

• while
• as
• with ... meanwhile

So the structure is:

• the captain received the medal
• huku his/her teammates were clapping

It helps paint the background action happening at the same time.

Because waki- shows an action happening at the same time as the main action.

Breakdown:

• wa- = they
• -ki- = while / in the process of
• piga = hit, strike, clap

So:

• wakipiga makofi = while they were clapping

If you used walipiga, that would just be a simple past statement: they clapped.
But wakipiga fits the idea of background action happening simultaneously.

Wenzake means his/her companions, colleagues, teammates, or associates, depending on context.

In this sentence, because the setting is a sports match, it most naturally means his/her teammates.

The ending -ake means his/her. So wenzake is basically his/her fellow people or his/her companions.

This is an idiomatic expression. Literally, kupiga often means to hit or to strike, but in many expressions it combines with another noun to create a new meaning.

So:

• kupiga makofi = to clap / to applaud

It is a standard expression, and learners should memorize it as a whole phrase.

The singular is kofi, but kofi usually means a slap. In the expression kupiga makofi, the plural makofi is the normal form used for clapping/applause.

So even though the words are related, you should not think of makofi here as simply slaps. In this context it clearly means clapping.

Because Swahili does not normally use articles like English a/an and the.

So:

• kapteni can mean a captain or the captain
• medali can mean a medal or the medal
• mechi can mean a match or the match

The exact meaning comes from context, not from a separate article.

Yes, very normal. The sentence is arranged like this:

• Baada ya mechi = time phrase
• kapteni alipokea medali = main clause
• mbele ya nyavu = place phrase
• huku wenzake wakipiga makofi = simultaneous/background action

This order sounds natural in Swahili and is a common way to build a vivid description.