With the UK’s Andy Murray already out, Söderling is now the title favourite amid an
impressive season in which he finished runner-up at Roland Garros and reached the quarter-finals at Wimbledon and the US Open.
Eighth seed Monfils won in commanding fashion at Montpellier last week, but the lively Frenchman was soon trailing a 4-1 in the first set and could find no way back against his hard-hitting opponent.
In the second set, Monfils struggled for a solution before eventually losing 6-3, 6-2.
Söderling will now face the winner from the quarter-final between fourth seed hometown favourite David Ferrer, who beat Italy’s Potito Starace 7-5, 6-4 for his fifth straight win in their matchups.
Frenchman Gilles Simon came through a gruelling contest against Russia’s Nikolay Davydenko 6-4, 6-7 (5/7), 6-3 and will now play Spain’s Marcel Granollers in the other semi-finals.
Simon has emerged as Davydenko’s nemesis, beating him the last four times they have met, but he will need to recover quickly before facing Granollers on Saturday.
“This is one of the best matches I have played this season. I had to fight right to the end,” said Simon, now ranked 52nd, but a former top-10 player.
Simon, who won in Metz at the end of September, eliminated one of the pre-tournament favourites in Fernando Verdasco in the last round and quickly broke Davydenko who was struggling against numerous unforced errors.
Davydenko fought back after losing his serve in the second set and took Simon to a tie-break, which he won 7-5. However, in the final set, the mistakes that riddled his game earlier returned and he lost 6-3.
Granollers appeared to be on his way home after being knocked out of the qualifiers but following an injury to France’s Jo-Wilfred Tsonga he returned as a lucky loser and has taken full advantage.
Dispatching countryman Benoît Paire in straight sets in the first round, the 67th seed has now gone on to eliminate in-form Juan Mónaco of Argentina, who is fresh from victory over top seed Murray.
Mónaco was clear favourite and had little trouble on his way to winning the first set 6-1. It was then, though, that Granollers, better known as a doubles player, began his fight back.
Mónaco began to more and more mistakes and Granollers took full advantage, winning 6-3 to take the game into a deciding set.
Mónaco looked in charge after breaking at 2-2, but Granollers responded by breaking twice as the Argentinian player faltered and winning the final set 6-4 is now through to his first ever Open 500 semi-final.