Мы сохранили копию на случай если потеряем сертификат участника.

Сохранили is the past tense, plural form of сохранить.

It tells you:

• the action happened in the past,
• the subject is we,
• and the verb is perfective, so it presents the action as completed: we saved / we kept.

Compare:

• мы сохраняли = we were saving / we used to save
• мы сохранили = we saved, we managed to keep

So here сохранили fits the idea of completing the action of keeping a copy.

Because копию is the accusative singular form of копия.

The noun копия is the direct object of the verb сохранили:

• сохранить что? → копию

Since копия is a feminine noun ending in -я, its accusative singular becomes -ю:

• nominative: копия
• accusative: копию

This is very common with feminine nouns:

• книга → книгу
• неделя → неделю
• копия → копию

It means in case (if).

The phrase introduces a possible future situation that someone wants to be prepared for:

• Мы сохранили копию на случай если потеряем сертификат участника.
• We kept a copy in case we lose the participant certificate.

A very common pattern in Russian is:

• на случай, если + clause

For example:

• Возьми зонт на случай, если пойдёт дождь.
• Take an umbrella in case it rains.

In standard written Russian, you would normally write:

Мы сохранили копию на случай, если потеряем сертификат участника.

So yes, a comma before если is normally expected here.

Why? Because если потеряем сертификат участника is a subordinate clause, and with на случай, если Russian usually separates that clause with a comma.

So for careful written Russian, the recommended version is:

Мы сохранили копию на случай, если потеряем сертификат участника.

Потеряем is the 1st person plural future form of the perfective verb потерять.

It is used because the sentence refers to a possible future event:

• we saved a copy now / earlier,
• in case later we lose the certificate.

Why not the others?

• теряем = we are losing / we lose (imperfective, present)
  • this would sound wrong here, because the sentence is about a possible future single event, not an ongoing process.
• потеряли = we lost
  • this would refer to something already completed in the past.

So потеряем is the natural choice for in case we lose.

Because сертификат is the direct object of потеряем, and for a masculine inanimate noun, the accusative singular is the same as the nominative singular.

So:

• nominative: сертификат
• accusative: сертификат

That is why Russian says:

• потерять сертификат = to lose a certificate

Compare with an animate masculine noun:

• я вижу студента Here the accusative is different because студент is animate.

But сертификат is inanimate, so its accusative looks unchanged.

Участника is genitive singular of участник.

It modifies сертификат and means something like:

• certificate of a participant
• or more naturally in English, participant certificate

So:

• сертификат участника = participant’s certificate / certificate of participation for a participant

This is a very common Russian pattern:

• паспорт студента = the student’s passport
• номер телефона = phone number
• центр города = city center

Russian often uses the genitive where English might use of or an apostrophe.

Yes, you could omit it.

Russian often leaves out subject pronouns when the verb already makes the subject clear:

• Сохранили копию... = We saved a copy...
• Мы сохранили копию... = We saved a copy...

Because сохранили clearly shows plural past, the subject can often be understood from context.

Why include мы then?

• for emphasis,
• for clarity,
• or simply because the speaker wants to make the subject explicit.

So both are possible, but мы сохранили... sounds completely natural.

Here случай is in the accusative singular.

The expression на случай is a fixed phrase meaning:

• for the case of
• more naturally, in case of / in case

The preposition на can take different cases depending on meaning, and in this expression it takes the accusative:

• на случай дождя
• на случай ошибки
• на случай, если...

So it is best to learn на случай as a set phrase.

Yes. Russian word order is flexible, though not completely free.

The version you have is natural and neutral:

• Мы сохранили копию на случай, если потеряем сертификат участника.

But other orders are also possible, depending on emphasis. For example:

• На случай, если потеряем сертификат участника, мы сохранили копию.
  • This puts more emphasis on the precaution.
• Копию мы сохранили на случай, если потеряем сертификат участника.
  • This emphasizes the copy.

So the meaning stays basically the same, but the focus shifts.

Yes, it is important.

Russian aspect matters a lot. Here потеряем comes from the perfective verb потерять, which presents the loss as a single completed event:

• if we lose it

That is exactly how English also thinks about this kind of event: one possible completed action in the future.

If you used an imperfective verb here, it would suggest an ongoing or repeated process, which does not fit as well.

So:

• если потеряем = if we lose is the normal choice.

The main stress pattern is:

Мы сохрани́ли ко́пию на слу́чай, е́сли потеря́ем сертифика́т уча́стника.

Word by word:

• мы
• сохрани́ли
• ко́пию
• на
• слу́чай
• е́сли
• потеря́ем
• сертифика́т
• уча́стника

Stress is important in Russian, so it is very useful to learn words together with their stress.

Yes. That is a good way to understand it.

Russian noun + genitive noun often corresponds to:

• of
• or the English possessive ’s
• or a noun used adjectivally

So сертификат участника may be translated depending on context as:

• the participant’s certificate
• certificate of the participant
• participant certificate

English chooses the most natural option for the context, but grammatically in Russian it is simply:

• сертификат
  • участника in the genitive.