Matavesi and co will take on Cardiff Blues at the Millennium Stadium as part of next weekend's Judgement Day, looking to cement their position - but they know Leinster are hot on their heels in fifth.
And 24-year-old Matavesi says there is no room for error if they are to finish the campaign with silverware.
"We have got three finals left to play and that starts with Cardiff," he told Wales Online. "I want to leave the season on a high with the Ospreys by winning the league title.
"When you lose a few key players to injuries and boys away on international duty you lose that little bit of rhythm.
"But the boys have played well since Leinster onwards and we are looking to finish the season on a high."
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