Playmaker Kaka claims Real Madrid still have room for improvement despite making it four league wins from four with their 2-0 triumph over Villarreal.

Kaka netted his first competitive goal for Madrid with a second-half penalty to help coach Manuel Pellegrini enjoy a happy return to the club he left in the summer and ensure the capital club continued their 100% record.

Only Madrid and their arch rivals Barcelona have won each of their opening four matches and they already boast a three-point advantage over the rest of the division, and if that was not bad enough for the other teams, Kaka believes there is more to come from his side as well.

"I'm very happy with the win, although we can still improve. To play how we want takes time, but I think we are on the right path," he said.

Cristiano Ronaldo gave Madrid the perfect start at El Madrigal by netting in the opening two minutes for the second successive match, and that took his tally to seven goals in five league and Champions League fixtures this season.

Ronaldo's fellow summer signing Kaka has found it more difficult to get off the mark, but he finally managed it last night after taking over the penalty duties from Ronaldo to roll home his side's second goal against 10-man Villarreal.

"I'm happy to have scored my first goal. It's been a great joy and I think I'll score more, but the most important thing is that the team won," the Brazilian added.

"When I scored, all my team-mates congratulated me. This shows that this team is very united, and my joy is the joy of the whole team."

Ronaldo, who netted twice against Xerez at the weekend, is enjoying a great start to the campaign having found himself under the spotlight a few weeks ago after struggling to find his best form during pre-season.

His goal last night saw him enter into the Madrid record books as the first player to score in the club's first four league matches of a season, and he is currently level with Lionel Messi and David Villa at the top of the scoring charts.

It has been a great start for both Ronaldo and Madrid, although the Portugal winger admits it was not easy against Villarreal, despite the home side losing their captain Gonzalo Rodriguez to a red card midway through the first half.

"It was a very difficult game against an opponent who have caused us many problems," the Portugal international said.

"We were able to score in the opening minutes and this is always important, but the key thing is that we've been able to to take away the three points.

"We've had to work hard because they've put us under pressure from the start, but little by little we warmed up and we were able to play how we like."