Матчбол остался у нас.

Because матчбол is a masculine singular noun in Russian, and the past-tense verb agrees with it.

• матчбол = masculine singular
• остался = masculine singular past tense of остаться

So the sentence is built around матчбол as the grammatical subject.

If the subject were feminine, you would get осталась; if neuter, осталось; if plural, остались.

Here остался means remained, was still left, or stayed.

The verb остаться is the perfective partner of оставаться and often suggests a resulting situation after something happened. In a sports context, this means that after the previous point or exchange, the team/player still had match point.

So the idea is not just simple existence, but that the match point did not disappear or change sides.

Russian very often expresses possession with у + genitive rather than with a verb like have.

So:

• У нас есть шанс = We have a chance
• У нас остался матчбол = We still had match point / Match point remained with us

Literally, у нас means something like by us or with us, but in many cases it functions like we have or it is on our side.

That is why Матчбол остался у нас sounds natural in Russian.

Нас is in the genitive case because it comes after the preposition у.

The pattern is:

• у + genitive

Examples:

• у меня
• у тебя
• у нас

So in this sentence:

• у нас = with us / on our side / in our possession

This is a very common structure in Russian, especially when talking about possession, availability, or whose side something is on.

Yes. Grammatically, матчбол is the subject.

That can feel unusual to an English speaker because the most natural English translation may be We still had match point, where we is the subject. But Russian structures it differently:

• Матчбол = subject
• остался = verb
• у нас = location/possession-like phrase

So a more literal version would be:

• Match point remained with us

Even if the natural English translation uses we, the Russian grammar is centered on матчбол.

Because остаться adds the idea of continuing after a change or after some event.

Compare:

• У нас был матчбол = We had match point
• У нас остался матчбол = We still had match point / match point remained with us

The second version implies that something happened, but despite that, the match point was still there. That makes it especially suitable in sports commentary or narration.

So остаться is more dynamic and context-sensitive than just быть.

Yes, absolutely.

Russian word order is flexible, and changing it often changes emphasis rather than basic meaning.

• Матчбол остался у нас: highlights match point
• У нас остался матчбол: highlights with us / on our side
• Остался у нас матчбол: more marked, often used for a special stylistic effect or in spoken emphasis

All of these can be possible depending on context. The original sentence sounds natural and gives prominence to the key sports concept: матчбол.

Yes, матчбол is a standard borrowed sports term in Russian. It is treated like a normal masculine noun ending in a consonant, so it does decline.

For example:

• nominative: матчбол
• genitive: матчбола
• dative: матчболу
• accusative: матчбол
• instrumental: матчболом
• prepositional: о матчболе

In your sentence, it is in the nominative singular because it is the subject.

The difference is mainly aspect.

• остался = perfective, focuses on the result
• оставался = imperfective, focuses on the ongoing situation

So:

• Матчбол остался у нас = Match point remained with us / We still had match point
  This presents the situation as a result after something happened.

• Матчбол оставался у нас = Match point was still with us / Match point kept remaining with us
  This sounds more descriptive, as if you are talking about an ongoing state in a broader narrative.

In sports commentary, остался is often the more natural choice when referring to the outcome of the latest point or sequence.

Not really. In this sentence, у нас is not mainly about physical location. It is about whose side the advantage/opportunity belongs to.

So Матчбол остался у нас does not mean that a ball was physically sitting near us. It means something more like:

• the match point was still ours
• the match point stayed on our side
• we still had match point

This is a very common Russian use of у + genitive: not literal location, but possession, control, or association.