British hopes at the
After four straight defeats on Bermuda's Great Sound, Ainslie's men desperately needed a win against Artemis to reignite their challenge in the qualifying battle for yachting's most prestigious regatta.
Ainslie had demanded improvements following a defeat to France's Groupama on Monday and his team delivered against Artemis, making a perfect start to lead immediately.
The Land Rover BAR boat pulled away at the first mark and steadily increased their lead to win by 30 seconds.
The win keeps Land Rover in third place in the standings with four points, one point behind second-placed Emirates Team New Zealand and holders Oracle, who top the standings with six points.
"We needed that one after the disappointment of yesterday," Ainslie said shortly after crossing the finish line.
"We made some changes to the boat, our speed was a lot better and we sailed a great race getting the boat around the course.
"It's a big win for us. We've got to keep developing from here and keep pushing forward."
Ainslie said the team had capitalised on Artemis's mistake in getting too close to the start line to take the lead.
"It was a nice start and from there the guys sailed brilliantly," the four-time Olympic champion said.
It was a second defeat of the day for Artemis, who had earlier been soundly beaten by Emirates Team New Zealand in the first race of the session.
The New Zealanders had snatched a dramatic last-gasp victory over the Swedes on Monday after late penalty went their way.
But there was no doubt about Tuesday's race as the Emirates team skippered by Peter Burling finished 1min 31sec ahead of the Swedes for a comfortable win.
In the day's other race, holders Oracle proved a class apart from France's Groupama, scoring a dominant win by 1min 56sec.
Oracle raced into a seven second lead from the starting line which had increased to 31 seconds by the bottom gate.
Skipper Jimmy Spithill eased up over the closing stages, after the crew spotted an issue with the wing sail.
"We had an issue, a bit of a failure in the wing," skipper Spithill said after the finish. "But that can happen.
"Put a bit of a band-aid on it and we were able to get through the race. But from that point on we were kind of in delivery mode."
Wednesday sees another day of racing, with Japan's SoftBank opening against Groupama before Ainslie's Land Rover BAR face the New Zealanders of Emirates.
Oracle will then race against Softbank before Groupama and Land Rover BAR complete the day's action.