However, they proved to be stubborn opposition for the visitors who were forced to come from behind to secure the win.
The home team included Bryn Gatland – the son of Lions coach Warren – and his conversion gave the Provincial Barbarians a 7-3 lead at the break.
Greig Laidlaw added to Johnny Sexton’s first-half penalty before Anthony Watson crossed to restore the visitors’ lead on 53 minutes.
Replacement Owen Farrell added the conversion but then missed a penalty, and the Lions survived a late surge from the hosts to hang on.
Warren Gatland’s side face all five Super Rugby teams, the New Zealand Maori, and the All Blacks, during the five-week tour, with their next match against the Blues on Wednesday (08:35 BST).
|Provincial Barbarians (7) 7|
|Tries: Anderson-Heather Cons: Gatland|
|British and Irish Lions (3) 13|
|Tries: Watson Cons: Farrell Pens: Sexton, Laidlaw|
Lions team: S Hogg; A Watson, J Joseph, B Te’o, T Seymour; J Sexton, G Laidlaw; J Marler, R Best, K Sinckler, AW Jones, I Henderson, R Moriarty, S Warburton, T Faletau.
Replacements: J George, M Vunipola, T Furlong, G Kruis, J Tipuric, R Webb, O Farrell, E Daly.