It is the racing tag that trainers would rather their horses didn't have.

And it is one being challenged by two of the best sprinters in the country.

Buffering and Rain Affair both have undeniable claims to being the best horse-in-training without a Group One win to their name.

Between them, they have been placed at the elite level 10 times without winning, seven of those second placings.

At Eagle Farm on Saturday, the two will clash in the BTC Cup and the Group One prize their respective trainers covet will again be up for grabs.

"They're both Group One maidens and I would say after Saturday one of them won't be," said Joe Pride, trainer of Rain Affair.

"Hopefully it's mine."

For the past two seasons, racing fans have been willing Queensland sprinter Buffering to claim an elite victory.

Three of his Group One placings have been behind the indomitable Black Caviar, another a head-bobbing loss to the outstanding Hay List.

Last winter he seemed destined to finally break through on home soil but again had to settle for seconds in both the Doomben 10,000 and Stradbroke Handicap.

Rain Affair is a little newer to the quest.

His first test at the top level was 15 months ago and since then he has finished second in three Group Ones and fourth in another.

Last start in the All Aged Stakes it took Black Caviar's half-brother All Too Hard to run him down.

Craig Williams and Corey Brown have partnered Rain Affair at his past two starts but with both having since headed overseas for riding stints, Pride has opted for Hugh Bowman.

"I had a few to choose from which is good, but with these things you've sometimes got to go with your gut feeling," Pride said.

"I just felt that Hugh would suit him."

Bowman and Pride have history when it comes to Group One success in Brisbane, combining to claim the 2005 Doomben 10,000 with Red Oog.

However, early markets favour Buffering to break his Group One hoodoo in the BTC Cup (1200m) with the Robert Heathcote-trained gelding the clear $2.60 favourite.

Last year's winner Sea Siren is next at $4.80, ahead of three-year-old Better Than Ready and Rain Affair who are joint third picks at $5.50.

Sea Siren will be having her final start in Keith Biggs' distinctive blue and pink colours with new owners Coolmore to decide her racing future after Saturday.