Bianca Andreescu's long-awaited return to action at the Internationaux de Strasbourg was a swift one. The No.1 seed needed just 61 minutes to dispatch qualifier Andrea Lazaro Garcia 6-1, 6-2.

Andreescu, who returned from a 15-month layoff at the start of 2021, has had a stop-start season so far. The Canadian put together a stellar run to the Miami final in March, but was forced to retire while trailing Ashleigh Barty in the title match after sustaining a foot injury. A positive COVID-19 test meant that she was unable to compete in Madrid or Rome as planned.

Indeed, this is not the first disrupted clay swing Andreescu has endured. In her 2019 breakout season, a shoulder injury ruled her out of any lead-up tournaments to Roland Garros, and would force her to withdraw from Paris after winning her first-round match over Marie Bouzkova.

Today's contest was thus only the second WTA-level main draw match on clay of Andreescu's career. The 2019 US Open champion did not struggle against World No.279 Lazaro Garcia, 26, a Spaniard who had come through qualifying to make her WTA main draw debut.

Lazaro Garcia had competed in last year's Prague WTA 125 event, and ousted top seed Monica Niculescu in the second round. But there would be no repeat upset for the Florida International University alumna here.

An error-strewn Lazaro Garcia was kept firmly at bay by Andreescu's power and spin. Andreescu was most troubled by herself: three double faults in the third game of the second set meant that she had to fend off break point for the only time in the match.

A strong serve did the trick, and Andreescu cruised from there. She sealed her third match point, and fifth break of serve, as Lazaro Garcia netted a forehand.

Andreescu zips past Lazaro Garcia in claycourt return: Strasbourg Highlights

Later on Monday, Sorana Cirstea claimed a 6-1, 2-6, 6-1 victory over former World No.1 Venus Williams in an hour and 45 minutes, upending the direction of their rivalry.

Cirstea had lost all three of her previous encounters with seven-time Grand Slam champion Williams, but in their first-ever meeting on clay, the Romanian prevailed in Williams's Strasbourg debut.

The win extends a 2021 resurgence for World No.61 Cirstea, who claimed her first singles title since 2008 in Istanbul and has seen her ranking improve 25 places since the end of last season.

Cirstea opened the match with a handful of blistering returns, breaking Williams at love in the very first game to set the tone. That was the first of the three times Cirstea broke the American in the opening frame, as she swept to the one-set lead.

Williams claimed the momentum in the second set, moving ahead by a break and holding onto that lead with key routine service games. However, in the decider, Cirstea notched another early break at love for 2-0, and was never challenged from there, closing the clash out with her fourth ace.

Cirstea will next face No.6 seed Zhang Shuai in the second round. Zhang ousted Misaki Doi, 7-5, 6-4 in a much-needed victory for the Chinese player -- she had been 0-7 in 2021 thus far, and had lost her last nine singles matches in total, dating back to her fourth-round showing at 2020 Roland Garros.

Also on Monday, No.4 seed Yulia Putintseva won one of the five longest matches of the season thus far, outlasting Rebecca Peterson 6-4, 3-6, 7-6(2) in a three-hour and 20-minute barnburner.

Peterson needed six set points in the last game of the second set before leveling the match at one set apiece. Peterson then had chances to serve out the match at 5-4 and 6-5 in the third set, but Putintseva broke back each time, sending the affair into a decisive third-set tiebreak.

Putintseva at last eased through the tiebreak to finish off the epic clash, winning her second straight meeting with Peterson to tie up their head-to-head at 2-2. Putintseva will now meet Jil Teichmann in the second round, after Teichmann defeated Anna Blinkova, 6-2, 6-3.

Former champ Garcia dazzles against Diyas: Strasbourg Highlights

Elsewhere, Caroline Garcia joined Alizé Cornet to make it two former champions in the second round. The 2016 winner defeated Zarina Diyas 7-5, 6-2, snatching the key first-set break at its conclusion before racing away with the second set.

In a battle of qualifiers, Belgium's Maryna Zanevska scored her first WTA main draw win since Bucharest 2018, defeating Yuliya Hatouka 6-2, 6-1. Hatouka, a 21-year-old Belarusian, was also making her WTA main draw debut.

Zanevska's second-round opponent: No.1 seed Andreescu.