Dimitri Mascarenhas says Hampshire must be more consistent if they are to defend their FL t20 title.
Holders Hampshire begin their challenge at home to Surrey on Wednesday.
"We won it last year, but we definitely weren't the best side," the ex-England international told BBC Radio Solent.
"What I want this year is for us to be the best side throughout, and be consistent. We're going to need to play some seriously good cricket as people will be coming for us."
The Royals claimed their second T20 title since the competition's inception in 2003 with a thrilling 10-run win over Yorkshire at Cardiff last summer.
Wednesday's opponent's Surrey - who include former Hampshire all-rounder Glenn Maxwell in their squad - have failed to lift the trophy since its first season.
However, all-rounder Mascarenhas, a doubt for the match at the Ageas Bowl with a back spasm, believes Surrey will be a formidable force in the competition this campaign.
"Surrey, on paper, have been the best team in T20 for the last four or five years," said the 35-year-old.
"But for one reason or another they haven't performed as well as they would have liked.
"This year I'm sure they'll be looking to turn it around and with a middle order of [Vikram] Solanki, [Ricky] Ponting and Azhar Mahmood, not forgetting [Steven] Davies and [Jason] Roy at the top.
"They've got some serious depth, and we're going to have to be on our game to beat them."