A 4-2 aggregate play-off triumph over Napoli ensured Bilbao, who finished fourth in La Liga last season, secured a spot in the group stages of Europe's premier club competition for the first time since the 1998-99 season.
Bilbao's domestic success was built on a foundation of solid home performances, with only Espanyol and Spanish champions Atletico Madrid leaving San Mames with a win.
Winger Muniain has now urged Bilbao to replicate that record in the Champions League, starting when they host Shakhtar on Wednesday.
"We must be strong at home, as we were last year in the league which helped us very much," he said at a news conference.
"We are not invincible at San Mames, but we feel very confident because we are always pushing to the maximum.
"It's good to start at home, it is always more comfortable. The first three points are vital."
Bilbao coach Ernesto Valverde has plenty of reasons to be optimistic about his side's chances in a seemingly wide open Group H which also includes Porto and BATE.
The Basque side has lost just once in their past 15 home encounters in Europe, with eight of those matches ending in victories.
However, Shakhtar have proved to be no pushovers in the Champions League.
The Ukrainian champions have proved to be quick starters in the past, with the club winning five of their six matchday one fixtures.
Shakhtar forward Luiz Adriano knows they can ill afford to take any of their group-stage rivals lightly as they attempt to start on a high note once again.
"We have played against Porto, we know their team and how difficult is to face them in Portugal," he said. "We don't know the other opponents and we must be careful.
"They are new teams and will give everything to show Europe why they have qualified. We must study well these teams in order to not be surprised by them."
Shakhtar, who are currently playing home matches in Lviv due to ongoing political tensions in Ukraine, had troubles off the pitch when the club's offices were occupied by armed men earlier this month.
But on the field, performances have been outstanding with the team winning all eight of their competitive matches this season.
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