Paintings by British-Ghanaian artist Lynette Yiadom-Boakye and South African painter Marlene Dumas outperformed expectations at Phillips on June 27.
Both artworks were sold to telephone bidders for about twice their estimates.
Yiadom-Boakye's "Leave A Brick Under The Maple", which was expected to fetch between £250,000 and £450,000, ended up hammering at £795,000 ($1 million).
This price, which did not break the artist's auction record, has likely been consolidated by her participation in the Ghanaian pavilion at the last Venice Biennale. Yiadom-Boakye will also have a retrospective at Tate Britain next May.
Marlene Dumas's "Losing (Her Meaning)", which had never been offered at auction before, was estimated to sell for between £400,000 and £600,000. It far exceeded expectations, climbing up to £1.2 million ($1.5 million). The canvas, which has been included in about 18 public exhibition, depicts a nude woman floating face down in water.
Specialist publications, including Artsy, have pointed out that a similar interest for works by female artists has been observed during Christie's and Sotheby's post-war and contemporary art sales. The auctions took place respectively on June 25 and 26.
African-American artist Tschabalala Self broke her auction record at Christie's with her 2015 oil-and-fabric collage, "Out Of Body." The painting, which was expected to fetch between £40,000 and £60,000, sold for £371,250 ($471,322) -- more than five times its high estimate.
Another record was set for American artist Kara Walker, whose "Four Idioms on Negro Art #4 Primitivism" went to an anonymous bidder for £395,256 (around $502,000). The painting, executed in 2015, depicts three figures in a ménage à trois while being aggressively brutalized by a police officer in riot gear.
On June 26, Toyin Oijh Odutola's paper piece "Compound Leaf" tripled its low estimate at Sotheby's, bringing in £471,000 (about $594,000). In addition to breaking her auction record, Odutola became the third highest selling Nigerian artist of all time.
London summer sales highlighted a growing interest for female and minority artists, with more established artists failing to shine.
Francis Bacon's 1975 "Self-Portrait, which was the top lot of Sotheby's contemporary art evening auction, went for £16.5 million (about $21 million), which is just above its low estimate of £15 million.
On June 25, Jean Dubuffet's "Cérémonie" fetched £8.72 million (around $11.1 million) at Christie's -- a price in the middle of its £7-million-to-£10 million estimate.
This year marks the first time since 2016 that all three auction houses held summer evening sales in London. None outperformed expectations as the evening sale total across Sotheby's, Christie's and Phillips was £150.1 million ($190.4 million).