Sri Lanka trail 0-1 in the three-match series, after Shivnarine Chanderpaul hit a six off the last ball to formalise a thrilling one-wicket victory for West Indies in the opening match on Thursday at the same venue.
"We made a few mistakes in the field in the first ODI, and probably gave away 15 or 20 runs which obviously in the end make a big difference," said Bayliss.
"So if we can minimise some of the mistakes which we made the results can be different. If we can get a few things go our way on the day, it can make all the difference."
Bayliss admitted that while he was disappointed with the result there was plenty which pleased him about the way his side played.
"The end-result is not a great one, but this sort of thing can happen," he said. "I thought we have played some of our best cricket, and I thought we also played some of our worst cricket, so we just have to find that middle ground and play well consistently.
"We showed great character getting back into the match, and to have a huge chance of winning the match after being 49 for five, I think says a lot about the character of the players in the team."
Bayliss is not surprised that West Indies have out-stepped his side in the last five days of cricket, after they won the second and final Test at the same venue by six wickets to earn a share of the series, and now won the opening ODI with literally the final act.
"They have played some good cricket as well," he said. "We have picked a young team for this ODI series, and we are very happy with the way they have performed.
"We have four very good bowlers sitting in the sheds at home, and as we have said, this is all about starting to set-up for the World Cup in 2011.
"The West Indies have got some very, very good players, and if they have a good day, it's going to be very difficult for us to win."
West Indies all-rounder Dwayne Bravo won the Man-of-the-Match award in the first ODI, after he collected a career-best four wickets for 32 runs from his quota of 10 overs, and then scored a rapid-fire 36 off 37 balls.
He shared a 59-run stand for the fifth wicket with Chanderpaul, as West Indies successfully chased Sri Lanka's 235 for seven.
Bravo believes the home team still has plenty of improvements to make if they are to win the second ODI and clinch the series.
"We're happy with the win, but there is a lot to improve on," he said. "We have to go back to the drawing board, have a good practice session on Friday, and look to seal the series on Saturday.
"We're happy with the win, but we would have been happier if we could have won the game with more wickets in hand."
Bravo noted that head coach John Dyson and assistant coach David Williams has injected a new level of faith into the side.
"One thing in the West Indies team now is that there is a lot of faith," he said. "What the coaches bring into this team is that the team gets closer to God.
"We pray three times a day, and I think that is something which is taking us through at this time, and we are seeing signs of improvement. We have to get rid of the simple mistakes, believe in ourselves, and He (God) will do the rest for us."
Bravo also disclosed that West Indies had some faith in Chanderpaul when it came down to the wire.
"We knew that Shiv was there, and once he got most of the strike, we were in with a chance," Bravo said.
"We knew it would have been difficult with two balls to get 10 runs, and with a bowler as experienced as Chaminda Vaas, you would back the bowling team, but Shiv has done it already on different occasions and it goes to show his experience."
The third match of the series is a day/night fixture next Tuesday, April 15, at the Beausejour Stadium in St. Lucia.