Samoa, who led 31-3 at half-time, let their concentration slip in the last minute when Loni Katoa scored a try.
"We played for 79 minutes and that last minute was a lapse of concentration," Tuigamala, the former Wigan rugby league player, said. "There was a lot of pressure put on us today to perform, for our own reputations, for our own career and for the country as well."
Bob Ross kicked three penalties and Winston Stanley scored a 76th-minute try on Saturday as Canada celebrated its second consecutive Pacific Rim title with a 22-11 victory over the United States in San Francisco.
After the referee sent off the US prop Bill LeClerc for fighting in the 69th minute, the Eagles' hopes diminished.
Stanley ran in his try and Ross finished the game with an 87th-minute penalty to complete the victory for Canada
Gareth Rees also scored a try and kicked a penalty for Canada, while Alatini Saulala scored a try for the United States.
Hong Kong beat Japan 41-23 yesterday in its last match before the British colony's reversion to China, taking second place in the Championship.
Before nearly 10,000 spectators at Tokyo's Prince Chichibu Memorial Rugby Ground, Japan stayed close until the last five minutes, when the Hong Kong backs worked the ball out to Luke Nagaro, who went over in the corner for his second try. Carl Murray kicked two penalties and contributed 16 points overall.
After an even first half, Japan came out strongly with Masaaki Sakata charging through to give his team a 15-10 lead. But Hong Kong gradually took control, playing for possession and keeping the ball in hand.
Japan had lost stand-off Kensuke Iwabuchi to injury after just five minutes and had to reshuffle the back line accordingly.
Massideo Ravazollo scored one of Italy's five tries and kicked two conversions and four penalties in Bulawayo on Saturday, helping his side to level the Test series with a 41-27 victory over Zimbabwe.
Paolo Taddio, Andrea Parattin, Tomasso Vicentin and Mario Di Rossi also touched down for Italy, who were 26-12 ahead at half-time.
Zimbabwe were undone by the kicking of Douglas Trevella, Antony Papenfus and Ken Tsimba, whose errant feet wasted any chance of matching last week's upset victory in Harare. In all the home side missed seven penalties and two conversions.
Ken Tsimba scored two tries, while Trevella and Brendan Dawson had one each. Tsimba also managed two conversions and a penalty.Reuse content