Simon Cowell's ITV talent show was watched by 9.67m (41.8%) between 8.30pm and 9.30pm, adding 489k (2.3%) on ITV1 +1.
As the end of the show drew near, a peak of 10.7m watched 9-year-old Malaki Paul's emotional audition. Britain's Got More Talent then grabbed a series high of 1.07m (4.9%) from 9.30pm (+1: 239k).
BBC One's The Voice UK logged a massive 9.33m (41.8%), peaking with 10.3m, but lost viewers for the second Saturday in a row.
However, it seems The Voice was hampered by questionable early evening scheduling from the BBC, as an old edition of My Family gave the singing contest only a 2.8m (14.7%) lead-in, while Pointless Celebrities took 3.97m (22.6%) from 5.35pm.
But My Family still beat ITV1's new Keith Lemon vehicle Lemonaid, which registered an audience of just 2.39m (12.6%) from 6.15pm, after which You've Been Framed amused 2.67m (12.3%).
Pitted against The Voice, The Cube could only muster 2.71m (12%) from 7.30pm (+1: 122k). A Benidorm repeat had 2.5m (11.6%) from 9.30pm (+1: 174k/1.1%).
Meanwhile, The National Lottery: In It To Win It (4.57m/18.8%) and Casualty (4.57m/20.3%) held up well for BBC One against Got Talent.
BBC Two's only new programme, I Love 1972, enthralled 2.18m (10.1%) at 9.30pm, while Channel 4's screening of Terminator Salvation attracted 1.66m (8.8%) from the same time.
Elsewhere, CSI: NY was Channel 5's only show to break the 1m mark with 1.28m (6.7%) in the 10pm hour.
Overall, BBC One extended its primetime lead over ITV1 with 28.5% against 19.5% (+1: 0.9%). BBC Two edged into third place with 6%, just ahead of Channel 4's 5.7% (+1: 0.6%), but far ahead of Channel 5's 3.6% (+1: 0.1%).
Foreign crime drama The Bridge continued with a decent 787k (3.3%) and 683k (3.5%) for BBC Four and BBC HD.
Things got worse for Steven Spielberg's Smash, delivering only 55k (0.3%) at 10pm on Sky Atlantic.
BARB ratings data supplied by Attentional