So when the Senators whittled a 13-point deficit down to five with two minutes remaining, finishing the game strong was an absolute must for the Cardinals.
Thanks to some heady play down the stretch, that's exactly what they did.
Greenwich tightened its defense in the final minutes and turned away Brien McMahon, 54-46 in a key FCIAC matchup.
"We saw this as a must-win game for us," said Barrett, who totaled 11 first-half points.
"We should have won Friday (a loss to Wilton) and we needed to rebound tonight. Hopefully, this starts a winning streak."
The Cardinals need to gain eight victories to earn a berth in the Class LL Tournament -- an event it hasn't qualified for in quite a while.
"This is our fifth win, so we need three more and we hope to get more than that," said DeCarlo, who scored six first-half points. "It was definitely a crucial game because there are not many games left in the season. We kept our heads clear and remembered what coach teaches us in practice."
McMahon (2-9) was led by sophomore point guard Kayla Croswell's game-high 22 points. Croswell's layup with 2.8 seconds remaining in overtime lifted the Senators past the Cards a year ago, 40-38.
"Our team played hard, played good defense and every time they were down they fought back," McMahon coach Mark McElveen said. "But Greenwich outrebounded us by a lot, which hurt us. We can't give teams four, five, six shots and not expect them to hit one."
Trailing 48-35 midway through the fourth quarter, the Senators quickly got back in the game. Junior Victoria Aguilar made a 3-pointer while being fouled and converted the ensuing free throw, cutting Greenwich's lead to 48-39 with 3:02 left. Back-to-back baskets from Croswell made it 48-43 with 2:00 left.
Unlike last season when the Cardinals saw the Senators force overtime, Greenwich sealed the deal Tuesday. Sophomore guard Leigh Galletta converted a layup while being fouled, then swished her free throw, putting GHS ahead 51-43 with 49 seconds left. Kockenmeister made a pair of foul shots in the final 30 seconds to ice the game.
For Greenwich coach Chrys Hernandez, watching her squad execute in crunch time against her alma mater was a welcome sight.
"We refocused toward the end of the game, took care of the ball and pulled it together when it counted," said Hernandez, who led the Senators to both the FCIAC and state finals her senior year at McMahon.
Leading 39-33 after three quarters, the Cardinals held McMahon scoreless the first 4:12 of the fourth, while building a 45-33 advantage. Barrett went back door for a layup, DeCarlo made a pair of baskets and Kockenmeister scored off a steal, putting the visitors in a 12-point hole.
Meanwhile, McMahon, which scored several baskets off its press-breaker in the first half, had trouble moving the ball upcourt against the Cards' 1-2-1-1 full court press in the second half.
"We had to make an adjustment in the second half because their point guard was quick and was breaking our double," Barrett said. "Leigh Galletta and Jamie (Kockenmeister) did a great job of grabbing those loose balls off the press."
Said McElveen: "We are a young team and because of that our players feel like they have to rush instead of taking their time. It's things that we're doing to ourselves that's hurting us."
Six straight fastbreak points from Kockenmeister put Greenwich up 13-6 in the first quarter. After the Senators (2-9) closed to within 18-14 on junior Jazmine Taylor's layup, DeCarlo hit a jumper and Barrett nailed a 3-pointer, making it 23-14 midway through the second quarter. Galletta scored six points, senior center Brittany Rodriguez, who played against her sister Sabrina, had five for GHS.
"After our loss to them last year by a basket, we had a lot of motivation to win," Kockenmeister said. "We knew we had to finish off the game strong if we wanted to win this game."
Aguilar had 12 points, while Sabrina Rodriguez added six for McMahon. Up next for Greenwich is a road game against Darien.
"Every time we step on the floor we know that's the team that stands between us and our goal of making it to states," Hernandez said.
GREENWICH 54, mcmahon 46
Kayla Croswell 11 0-2 22; Alleya Jenkins 1 0-2 2; Yasmine Walker 0 0-0 0; Jazmine Taylor 2 0-2 4; Victoria Aguilar 4 1-1 12; Sabrina Rodriguez 3 0-0 6; Kiara Velez 0 0-0 0; Olivia Rosado 0 0-0 0; Fabiola Bachinelo 0 0-0 0. Totals: 21 1-7 46.
Caroline Barrett 6 4-5 18; Leigh Galletta 2 2-3 6; Alexa Moses 0 0-0 0; Jamie Kockenmeister 6 1-2 13; Brittany Rodriguez 2 1-3 5; Rebecca DeCarlo 3 4-6 10; Rebecca Kural 0 1-2 1; Caroline Beneville 0 1-2 1. Totals: 19 14-23 54.
3-pointers: BM -- Aguilar 3; G -- Barrett 2.
MCMAHON.........................8 14 11 13 -- 46
GREENWICH.....................13 14 12 15 -- 54
Records: Greenwich 5-7; McMahon 2-9.