The Samoa-born centre crossed twice under the Sapporo Dome roof in a first half that ended with England well ahead at 18-3.
And second-half scores from hooker Jamie George and replacement Luke Cowan-Dickie saw England secure a bonus point for four tries, a result that could be crucial in a tight Pool C.
England appeared to be playing within themselves to avoid injuries to key players.
Coach Eddie Jones said: “The thing about the World Cup, having been to a few, is the World Cup is not a 100-metre sprint. So you don’t have to come out of the blocks and be absolutely fantastic now, what you have to be is steady, you have to be prudent and you have to have a mindset of improvement and that’s what we’ve got.”
Captain Owen Farrell, who kicked 15 points, added: “To come away with a bonus-point win is always a good start to a World Cup. There are still some mistakes that we can look at and that’s the exciting thing. We’ve still got a lot more in us.”
Tonga, who’ve lost more than 20 players to other World Cup nations, were vastly improved from the side that suffered a 92-7 warm-up thrashing by world champions New Zealand in Hamilton this month.
“We didn’t play well against the All Blacks and we caught them on a bloody good day,” said Tonga coach Toutai Kefu. “Today’s effort was a much improved effort.” (AFP)