The Portugal international completed his £3m move to the Scottish giants on a three-year deal.
Mendes scored five goals in 68 appearances for Pompey after signing from Spurs in 2006.
The 29-year-old's last-ditch wonder goal winner against Manchester City is credited with being the catalyst which kickstarted the Great Escape following his arrival.
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The full article contains 87 words and appears in The News newspaper.