Taranaki produced a gutsy performance and matched the Lions until a 48th-minute try from skipper Martin Corry saw the balance of power shift in the tourists' favour.
England fly-half Charlie Hodgson turned in an impressive performance - he booted 16 points and pulled the strings with confidence - while his half-back partner Chris Cusiter caught the eye.
Shane Horgan also crossed while the lively Geordan Murphy finished with a brace - but Taranaki were in control early on with Lifeimi Mafi and Chris Masoe punching big holes in midfield.
The Lions touched down in the 10th minute when Horgan caught Hodgson's crossfield kick and fed Murphy, who sprinted over but referee Kelvin Deaker had spotted a forward pass and disallowed the try.
Danny Grewcock and Taranaki skipper Paul Tito were given a warning in the 14th minute after exchanging punches and the deadlock was broken shortly after when Hodgson landed a penalty.
Both sides showed some promising moments in attack - the Lions eventually running out of players on one move while Taranaki went desperately close to scoring before conceding another crucial turnover.
The Lions were not out of trouble as a loose pass from Cusiter allowed Taranaki to relaunch their assault and when the ball slipped out of a ruck, openside Masoe was present to pick up and dive over.
Sam Young added the conversion but Hodgson slashed the deficit with a penalty and his England team-mate Ollie Smith was prominent as the Lions finished the first half with a flurry.
They were under the cosh early in the second period, however, as Mark Stewart weaved his way into space to put Taranaki in a strong position but they managed to break free and take the lead for the first time in the match.
Denis Hickie's persistence led to the initial breakthrough with the ball finding Hodgson via Cusiter and the Sale fly-half fed Corry, who just got the ball down in the corner despite a superb challenge from Andrew Hore.
Hore was then dispatched to the sin-bin in the 54th minute for lying on the wrong side of a ruck, Hodgson landed the penalty and then hit another to give the Lions a healthy 10-point cushion.
Horgan put the result beyond doubt with a 67th-minute try and Murphy then added two more in the last 10 minutes as Taranaki's brave challenge wilted, although there was still time for Brendon Watt to add an injury-time touchdown for the home side.