Strong competition for a number of key works gave a major lift to the latest round of Old Master auctions in London.

While some of the lesser material on offer met with flatter demand, certain pictures seemed to benefit from both greater international interest as well as some crossover bidding from buyers who usually focus on other sectors.

This was particularly the case at Sotheby's evening sale last night as bidders from 33 countries participated in the auction, the highest ever at one their Old Master sales. The star lot of the night was El Greco's (1541-1614) Saint Dominic in Prayer, a powerful and expressive example of his many devotional pictures of saints.

The 2ft 6in x 23in (75 x 58cm) oil on canvas had never been offered at auction before and came from the collection of the late Dr Gustav Rau whose collection is being sold to benefit UNICEF Germany. It was estimated at £3m-5m.

Few such works remain in private hands and, on the night, it duly attracted three interested parties on the telephone. As the bidding reached £7.1m, the saleroom staff at the front of the room had to scramble as the phone line of the eventual buyer was temporarily lost. Meanwhile the unflappable auctioneer Henry Wyndham quipped from the rostrum: "Don't worry, I'm here all day."

With the phone line restored, the painting was eventually knocked down at £8.1m to the aforementioned buyer who was operating through a Russia-speaking member of Sotheby's client services department.

The price was a record for El Greco, beating the premium-inclusive £3.5m seen for Christ on the Cross back in July 2000 at Sotheby's London which was bought by the Getty Museum.

Sotheby's co-chairman of Old Master paintings Alex Bell said after the sale that the current picture "drew bidding beyond the traditional Old Master Market" and confirmed that there had also been underbidding from Asia.

"We're now firmly in a new era where clients from new markets are collecting Old Masters in new ways," he said. "Our response has been to offer the most exciting and diverse works we can find - and to present them a more contemporary way."

Another El Greco at Sotheby's was also knocked down to a Russia-speaking client. It was in fact another version of Christ on the Cross although around twice the size of the work they sold in the same room back in 2000. The current picture came to auction from descendants of the Spanish artist Ignacio Zuloaga but, with bidders clearly favouring the Saint Dominic picture which was the more arresting image, this example sold at a low-estimate £3m.

Vernet's Avignon

Elsewhere at Sotheby's, a number of other works made impressive prices. Among the eight artists' records was the £4.7m seen for A View of Avignon by Claude-Joseph Vernet (1714-1789) which drew interest on the phone but sold to a buyer in the room.

A handsome vista from 1757, it was the artist's only recorded view of his birthplace. The 3ft 3in x 6ft (99cm x 1.83m) oil on canvas showed the Papal Palace of Avignon, the medieval walls and the ruins of the 12th century Pont Saint-Bénezet to the left.

Consigned by an English vendor whose father had bought it from London dealers Arthur Tooth & Sons in the 1950s, it was in excellent condition and was estimated at £3m-5m.

The previous high for Vernet was a seascape which made $6.2m (£4.1m) at Sotheby's New York in January 2011.

Ruysch Record

Among a number of Dutch golden age paintings doing well was a still life by Rachel Ruysch (1664-1750). Estimated at £1m-1.5m, the 2ft 11in x 2ft 4in (89 x 71cm) oil on canvas from 1710 was a particularly fine example with exuberant roses, tuilips and other flowers as well as a butterfly on one of the stems and a bee in the sunflower. When originally commissioned, the artist had been paid a substantial 1300 guilders for the picture, while when it last it sold at auction at Christie's in 1912 it made 200 guineas.

On the night, it drew two bidders in the room and one on the phone, selling to a UK dealer at £1.4m. The price was a record for a Ruysch and also for an Old Master by a female artist.

Overall, Sotheby's sale saw 37 of the 47 lots sold (79%) and generated a hammer total of £30.1m which was well within the £23.4m-36.8m presale estimate.

Canaletto in Demand

Things were a bit tougher going at Christie's sale the night before as the £20.4m hammer total was below the £29.5m-44.6m presale estimate. Here, 36 of the 52 lots sold (69%).

The results would have looked much better had the top rated picture, Jan Steen's (1626-1679) Easy Come, Easy Go, managed to get away. The interior scene failed to draw a single bid against a hefty-looking estimate of £7m-10m although the auctioneers insisted afterwards that their pitch was in line with another large-scale Steen which had sold privately to the Rijksmuseum roughly nine years ago.

The auction was led by a Canaletto (1697-1768) view of Venice which drew decent interest against a £4m-6m estimate and was eventually knocked down to an anonymous phone bidder at £7.5m.

The Molo, Venice, from the Bacino di San Marco was one of the artist's glittering verdute and this 2ft 3in x 3ft 9in (69cm x 1.13m) oil on canvas was deemed as good a work by the artist to have appeared at auction since a number of top quality examples came up in 2005 (including the record view of the Grand Canal that took £16.6m at Sotheby's).

Elsewhere at Christie's and showing the selectivity of the market, two works by Lucas Cranach the Elder (1472-1553) met with contrasting fates. While a portrait of Cardinal Albert von Brandenburg (depicted as St Jerome) found no takers against a £1.5m-2m estimate, the signed oil on panel Christ on the Cross drew a strong telephone competition against a £500,000-800,000 pitch selling to a European dealer at £960,000.

English Ladies

As for the portraits at the sale, a Peter Paul Rubens (1577-1640) painting of a bearded man got away on low estimate to a telephone buyer at £1.5m but two English portraits generated much better bidding.

Sir Thomas Lawrence's (1769-1830) half-length depiction of Emily, Lady Berkeley was an early work which was exhibited at the Royal Academy in 1791. The 2ft 6in x 2ft 1in (77 x 64cm) oil on canvas was billed as a "vivacious and alluring portrait" which epitomised the qualities that underpinned Lawrence's meteoric career and established him the dominant force in British portraiture at the time.

It came completely fresh to the market and, in terms of its condition, it was very well preserved. Estimated at £400,000-600,000, it sold at £750,000 to an American private buyer bidding on the phone.

A few lots later an even stronger competition came for George Romney's (1734-1802) half length portrait of Elizabeth Ramus. Another striking painting of an attractive subject (and an even more youthful one), the 2ft 6in x 2ft 1in (76 x 64cm) oil on canvas came from the collection of Lord and Lady Hambleden and was appearing at auction for the first time since 1882.

Four bidders here were in contention, including the eventual buyer who was on the telephone and dramatically drove the bidding up in increments of £50,000. Eventually knocked down at £450,000, it fetched the second highest price for the artist at auction, only behind the $690,000 (£485,060) seen for Romney's portrait of Lady Sullivan sold at Sotheby's New York in January 2002.

The buyer's premium at both Sotheby's and Christie's was 25/20/12%.