Gatland hailed Saturday's Lions captain O'Mahony as a man who can bring the intangible will to win that has underscored Munster's modern-era success.
'But this tour isn't about Sam Warburton, it's about putting the squad first.
Coach Warren Gatland wanted his Lions to be tested before they faced the All Blacks and on what is the most punishing of tours, this was just that.
"This result hits the momentum a little bit", said Warburton after he played for 68 minutes.
Kyle Sinckler has told the British & Irish Lions exactly how to respond to the growing campaign in New Zealand to undermine their scrum - "Say nothing". Guys are well prepared, the recovery structure we have is excellent, so no excuses, we're getting stuck in, in training.
Gatland is anxious the Lions can not stop giving away needless penalties and admitted they "shot themselves in the foot" in Dunedin losing 23-22 to the Highlanders from 22-13 ahead.
Gatland was perplexed by several rulings but didn't want to dwell on them.
Marty Banks won the game for the home side when he slotted a 74th minute penalty, however, two powerful scrums from their replacement front rowers had given them the field position for the flyhalf to seal the opportunity.
Elliot Daly's monster last-gasp kick was a chance for the Lions to grab it back but his 57-metre pot shot couldn't find the target.
Gatland, however, felt the inconsistency was due to the different interpretations between Frenchman Raynal and Australian Angus Gardner, who was in control on Tuesday. You can not win Test matches with a count that high.
Brian, who is president of Letchworth Rugby Club, was inspired to take up his pen to write in praise of that unique institution, the British and Irish Lions, which tours only once every four years to either New Zealand, Australia or South Africa.
"We gave away too much possession at the breakdown, our first and second arrivals weren't there quick enough and that's something we spoke about during the game", Warburton said.
"We scored a couple of nice tries and probably missed a couple", Gatland said.
Ben Te'o will take the 12 shirt for Saturday's Maori All Blacks clash in Rotorua with Sexton starting at 10 - but Farrell is on the bench and could easily join the fray in midfield.
Sopoaga's second penalty was followed by a try to Lions skipper Sam Warburton, the flanker capping a busy night by stretching out to score under the crossbar to put his team 22-13 clear.
The hosts tested fullback Jared Payne under the high ball early but he proved up to the challenge, prompting them to send the ball wide.
The Lions produced a brilliant try to Joseph in which their backs at last showed finishing skill.style="text-align: center;"