El equipo rival atacaba rápido, pero el marcador seguía a nuestro favor.

In Spanish, many descriptive adjectives usually come after the noun, and rival works that way here.

• el equipo rival = the opposing team
• el rival equipo would sound unusual or literary in this context

So rival is functioning like an adjective meaning opposing or enemy/opponent.

Atacaba is the imperfect of atacar. It is used here because the sentence describes an action that was ongoing, repeated, or part of the background in the past.

So el equipo rival atacaba rápido suggests something like:

• The other team was attacking quickly
• The other team kept attacking quickly

If you used the preterite, such as atacó, it would sound more like they attacked as a completed event.

In Spanish, it is very common to use an adjective like rápido adverbially, especially in everyday language.

So both of these can work:

• atacaba rápido
• atacaba rápidamente

But rápido sounds more natural and common in sports commentary or casual narration.

It is similar to English using fast instead of quickly in some contexts.

Pero means but and is used when the second part of the sentence contrasts with the first, but does not directly correct it.

Here we have:

• The opposing team was attacking quickly, but the scoreboard was still in our favour.

That is a contrast, so pero is correct.

Sino is used after a negative statement to mean something like but rather:

• No atacaban despacio, sino rápido.
• They weren’t attacking slowly, but rather quickly.

So in your sentence, pero is the right choice.

Seguía is the imperfect of seguir, and it fits because it describes a continuing state in the past.

• el marcador seguía a nuestro favor = the score was still in our favour / remained in our favour

The idea is not that the score changed at one specific moment, but that it continued to be favourable during that period.

This matches the ongoing background feeling created by atacaba.

Here seguir means to continue or to remain.

So:

• seguía a nuestro favor = was still in our favour / remained in our favour

This is a very common use of seguir:

• La puerta seguía abierta = The door was still open
• Seguíamos allí = We were still there

A nuestro favor is a fixed expression meaning:

• in our favour
• on our side
• favouring us

In sports, it usually means that the score or situation benefits your team.

Examples:

• El partido estaba a nuestro favor. = The match was going our way.
• El resultado quedó a su favor. = The result ended in their favour.

In this sentence, a favor is part of a set expression.

• estar a favor de = to be in favour of
• jugar a favor de alguien = to work in someone’s favour

With sports scores or situations, Spanish often uses a favor:

• dos goles a favor
• el marcador a nuestro favor

You may also see en nuestro favor in other contexts, especially when talking about evidence, arguments, or circumstances:

• Todo estaba en nuestro favor. = Everything was in our favour.

But with marcador, a nuestro favor is very natural.

In sports, el marcador commonly refers to:

• the score
• the scoreboard
• the displayed result of the match

Depending on context, English might translate it as the score rather than literally the scoreboard.

Other words:

• la puntuación = the score/scoring, but often sounds a bit more general
• la marca usually means mark, brand, or record, not the normal word for the score in a match

So el marcador is very natural in a sports context.

Yes, that is possible, but in natural English it is often better translated as:

• the score was still in our favour
• we were still ahead
• the score still favoured us

Spanish often uses marcador where English prefers score rather than scoreboard.

So a more natural translation usually focuses on the result, not the physical board.

Because favor here takes a possessive structure:

• a nuestro favor = in our favour

Spanish normally uses a possessive adjective before a noun in cases like this:

• nuestro equipo = our team
• nuestra ventaja = our advantage
• a nuestro favor = in our favour

Using de nosotros here would sound unnatural.

Yes, that is grammatically correct. Spanish word order is fairly flexible, and your version is possible.

However, the original order gives a particular flow:

1. first, the pressure: el equipo rival atacaba rápido
2. then, the contrast: pero el marcador seguía a nuestro favor

That makes it feel like:

• They were attacking hard, but we were still ahead.

So the original order is probably preferred for style and emphasis.

The accent in seguía shows the stress and helps indicate the vowel pattern.

Without going too deep into spelling rules, seguía is pronounced with a break between the vowels:

• se-guí-a

The accent tells you the stressed syllable is guí.

This is common in forms of seguir:

• seguía
• seguían

Yes, very much. It sounds natural in a sports context, especially in a match report or spoken summary.

It has two typical features of sports narration:

• atacaba rápido = dynamic action
• el marcador seguía a nuestro favor = focus on the score/status

A native speaker could easily use this when describing a football match, for example.