The 37-year-old Lara had demanded steady improvement from his men from match-to-match in the series against the under-strength Zimbabweans, as they prepare for a much tougher assignment against India later this month.
"I am happier, but I still think there are areas which we can work on, and I think the guys batted really well in this game," he said on Monday.
"It's unfortunate though, that no one went on to score a hundred and this is something we will have to work on in the remaining matches."
Prior to Sunday's match, Lara had expressed disappointment that Saturday's third ODI had been cancelled because of rain, but he was glad his side had a chance to play and score an outright win that gives them a 3-0 lead in the seven-match series.
"I think the man upstairs smiled on us, and we were able to get not just a hit out, but the entire 100 overs, so it was great to be here," he said.
"This is the last international match at Bourda and what a fitting end it would have been had Shivnarine (Chanderpaul) gone on to score a hundred at his home ground.
"This was unfortunate, but this ground has a very strong history, and we are proud to play here, and we will miss the unique atmosphere that we have grown accustomed to here."
Terrence Duffin, the Zimbabwe captain, agreed that the ground had a wonderful atmosphere, but his thoughts were concentrated on what went wrong with his bowling that allowed West Indies to plunder 333 for six from their allocation of 50 overs.
"We struggled to find the areas in the beginning and we struggled to bowl to a plan," he said.
"It was good to see the batting coming along though, and it was good to see that we can start making good scores.
"Obviously losing two early wickets, it put us down a bit, but it was good on the boys that they fought hard in the middle order, and helped us to reach a respectable total. It will definitely toughen us up."
Duffin was one of two wickets that West Indies tyro Fidel Edwards removed in the first over of the chase and set back the visitors, who eventually reached 251 for seven off their allotment of 50 overs.
For Chanderpaul, who was named Man-of-the-Match, it was special occasion, since Bourda is where he learnt his cricket playing for the Georgetown Cricket Club, made his Test debut, and is the main venue in his homeland before a new stadium is inaugurated for the 2007 ICC World Cup in the West Indies.
"It would have been nice to get a hundred in the last international game at Bourda," he said.
"I hope that when we move over to the new venue, it can give me the same kind of returns with the bat that I have had with Bourda."
Chanderpaul top-scored for West Indies with 93, his first score over 50 for the last nine months when he was distracted by the burden of captaincy, but he concluded he was still struggling a bit and needed some more time in the middle to fine his best form.
The two sides on Monday wing their way to St. Lucia, where they will contest the first day/night ODI in the Caribbean on Wednesday at the Beausejour Stadium, before heading to Trinidad for the last two games in the series on the weekend at Queen's Park Oval.
West Indies also won the first two ODIs by five wickets and 98 runs last weekend in Antigua.