Infantino defended both innovations saying that television audiences and revenue around the world would be boosted by the changes while the first round of matches had already produced some surprises.
There has been widespread criticism that expanding the finals from 16 to 24 teams would devalue what was regarded as "the perfect format" but Infantino took the opposite viewpoint.
"It is in line with the objectives of UEFA which are to develop football in Europe. We can move from 16 to 24 because the quality is there in Europe," he said at the Leaders In Sport Summit.
"Of the top 32 teams in the world, 20 are European. One of the criticisms is that some of the games in the qualifiers become uncompetitive but I think we can see from Matchday One in September, something that we didn't expect.
"The fact that 24 teams can qualify gives a chance to almost all the teams and this has brought a whole new dynamic to the qualifying competition because everyone, at least at the beginning, believes they have a real chance of playing in the finals.
"We have seen Cyprus beating Bosnia, the Czech Republic beating the Netherlands and Albania beating Portugal, so we have seen some amazing results already and this new dynamic can make the qualifiers even more interesting."
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There are nine qualifying groups with the top two in each going through to the finals automatically along with the best third-placed team.
The remaining eight third placed teams play off over two legs with the four winners joining the other 19 and hosts France in the finals in two years time.
As well as more teams qualifying than before, the "Week of Football" concept means matches are spread out from Thursday to Tuesday with at least a third of the games being played on weekends.
Infantino said this gives fans a better chance of following not just their own team but others on TV and this increased television coverage would boost interest, viewing figures and revenue.
"Until now, we played double-headers with matches on Friday and Tuesday, and we thought why are we leaving the weekend without football?
"If you look at national viewing figures, England against San Marino for example will have more viewers than any Champions League match but until now, apart from the World Cup or a European championship, everyone was focused on their own team.
"Now we start on Thursday with a standard kickoff time and two kickoff times at the weekends, and the reaction has been very positive.
"Some new channels have even been created so now you can watch all the matches of every member association. We have sold the rights globally and the viewing figures have been extremely promising.
"On Matchday One some 800,000 people watched the Netherlands versus the Czech Republic for example in the UK, figures were up in Germany and Italy by 30 percent.
"The pie is growing and so far we have generated 40 percent more revenue than before."
He added that clubs will benefit as a result because "two times out of three their players will come back from their national teams one or two days earlier than before."
