If Andy Murray hopes to take Novak Djokovic's No 1 ranking at the Paris Masters this week, he must play significantly better than he did in a scrappy win over Fernando Verdasco in the second round on Wednesday.

Murray will become No 1 if he wins the tournament and Djokovic - winner for the past three years - does not reach the final.

Djokovic began his quest for a fourth straight Paris Masters crown by easing past Luxembourg's Gilles Muller 6-3, 6-4.

Murray is full of confidence after three straight tournament wins, but needed to scrap hard to beat Verdasco 6-3, 6-7 (5), 7-5.

The Scot's 12th win in 13 career matches against the Spaniard was unconvincing and he needed 2 ? hours to prevail.

"I didn't feel that comfortable," Murray said. "The match wasn't played on my terms. He was dictating the points."

It was scrappy stuff as they conceded 25 break-point chances between them.

"It wasn't the best match," said Murray, who next faces 13th-seeded Frenchman Lucas Pouille. "I will play better tomorrow."

US Open champion Stan Wawrinka will not get that chance.

The third-ranked Swiss lost to Germany's Jan-Lennard Struff 3-6, 7-6 (6), 7-6 (1), letting Struff off the hook when he failed to convert a match point at 6-5 in the tiebreaker.

There was no such drama for Djokovic.

Celebrating his win several hours earlier, he tapped his hand against his heart and made a throwing gesture to all four sides of the court as if to share the moment with the crowd.

Djokovic has a special bond with Paris, also winning this tournament in 2009 and clinching the French Open in June to complete his collection of all four majors.

Djokovic saved the only break point he faced in the second set and was clinical when it mattered.

With the score 4-4 at 30-40, Muller sent down a strong serve that Djokovic returned with venom. It surprised Muller, who swatted a forehand into the net.

The Serb sealed victory on his first match point with an ace straight down the middle.

He next faces Grigor Dimitrov in the third round and has a 5-1 career record against the 14th-seeded Bulgarian, while Murray leads Pouille 2-0.

Pouille earlier advanced by beating Spaniard Feliciano Lopez 6-7 (1), 6-3, 6-4.

"He's a big hitter," Murray said of Pouille. "He takes chances."

Murray led the second set against Verdasco 4-2, but after the Spaniard leveled the match in a tense tiebreaker, Murray swiped his racket angrily through the air and then yelled at himself when he sat down.

His frustration was not over.

Murray broke to lead 2-0 in the deciding set, but Verdasco held on. Finally, Murray broke him to love in the 12th game to win.

Wawrinka was out of sorts in his clash.

In the first set, he made 20 unforced errors and gave nine break-point chances, but Struff failed to convert any of them.

When Struff eventually broke Wawrinka in the seventh game of the deciding set - on the 14th attempt - Wawrinka threw his racket to the ground.

Serving for the match at 5-4, Struff returned the favor, double-faulting to hand Wawrinka a reprieve.

But Wawrinka fell apart in the tiebreaker as Struff advanced to meet big-serving American John Isner.

Earlier, fifth-seeded Kei Nishikori of Japan downed Viktor Troicki of Serbia 6-2, 7-5 and next faces 11th-seeded Jo-Wilfred Tsonga of France, who beat Spaniard Albert Ramos-Vinolas 6-3, 6-4.

David Goffin kept alive his slim chances of qualifying for the season-ending ATP finals in London by defeating Nicolas Mahut 7-6 (5), 6-3.