Arsene Wenger has said his decision to switch to three at the back for his side's victory over Middlesbrough - the first time he’s done so since May 1997 - proves he still’s capable of changing his outlook as a manager.

The Frenchman made six changes to the side that was humiliated at Selhurst Park last week, with Hector Bellerin notably dropping to the bench to make way for a three-man defence led by the returning Laurent Koscielny.

Despite putting in an unconvincing performance, Arsenal secured all three points to keep their faint hopes of Champions League football alive.

Middlesbrough vs Arsenal player ratings Show all 22 1 /22 Middlesbrough vs Arsenal player ratings Middlesbrough vs Arsenal player ratings Brad Guzan – 6 out of 10 Dealt with most that Arsenal threw at him but should have done much better with Sanchez’s free-kick. Getty Middlesbrough vs Arsenal player ratings Antonio Barragán - 6 Solid if unspectacular night on the right side of defence. Getty Middlesbrough vs Arsenal player ratings Ben Gibson – 7 Marshalled Giroud well and handled the Frenchman’s physicality without too much trouble. Getty Middlesbrough vs Arsenal player ratings Daniel Ayala -7 Capable in defence but should’ve done better with second-half header. Getty Middlesbrough vs Arsenal player ratings George Friend - 6 Exposed by Oxlade-Chamberlain at times but solid enough in relief of the injured Fabio. Getty Middlesbrough vs Arsenal player ratings Adam Clayton – 5 Typically workmanlike in defence but a poor challenge cost Boro dearly from the resulting Sanchez free-kick. Getty Middlesbrough vs Arsenal player ratings Marten de Roon – 6 Failed to really assert himself on the game. Getty Middlesbrough vs Arsenal player ratings Grant Leadbitter – 6 Ugly first-half tackle on Ozil could’ve earned him more than just a yellow but showed well in attack. Getty Middlesbrough vs Arsenal player ratings Stewart Downing - 7 Rolled back the years with an inch-perfect ball for Negredo’s goal. Getty Middlesbrough vs Arsenal player ratings Alvaro Negredo – 7 Quiet night as the home side’s focal point but took his goal with a poacher’s instinct. Getty Middlesbrough vs Arsenal player ratings Gaston Ramírez – 7 Boro’s brightest attacking threat and looked the home side’s most likely to break the Gunners back line down. Getty Middlesbrough vs Arsenal player ratings Petr Cech - 6 Not tested a great deal and deserved better from his defence for Negredo’s goal. Getty Middlesbrough vs Arsenal player ratings Gabriel – 6 Always on the edge of an utter calamity the Brazilian managed to avoid any tonight and looked better in a three. Getty Middlesbrough vs Arsenal player ratings Laurent Koscielny – 7 Arsenal’s best defender but will have wanted to do better with Negredo’s goal. Getty Middlesbrough vs Arsenal player ratings Rob Holding – 7 Definitely a player for the future if not right now. Getty Middlesbrough vs Arsenal player ratings Alex Oxlade-Chamberlain – 7 Pushed on well down the right flank and offered positional discipline going the other way too. Getty Middlesbrough vs Arsenal player ratings Aaron Ramsey – 7 Neat and tidy as ever and added a dash of quality with a deliciously composed chested knock down for Ozil’s goal. Getty Middlesbrough vs Arsenal player ratings Granit Xhaka – 7 Doesn’t know whether he’s coming or going but plenty of energy if not so much discipline from the Swiss. Getty Middlesbrough vs Arsenal player ratings Nacho Monreal – 7 Added some good balance on the left and thrived with the added attacking responsibility. Still a little clumsy in the defence. Getty Middlesbrough vs Arsenal player ratings Mesut Özil – 7 Took his goal with the composure required and added the class when the Gunners needed it most. Getty Middlesbrough vs Arsenal player ratings Alexis Sánchez – 8 Not one of the Chilean’s best games yet was still the outstanding performer scoring one and creating another. Getty Middlesbrough vs Arsenal player ratings Olivier Giroud – 7 Didn’t threaten as much as he would’ve liked but added the focal point that Arsenal lack with Sanchez up top. Getty

Speaking after the game, Wenger laughed that even after 20 years he can still change.

"First time in 20 years, yes, and that shows you that at even at my age you can change," he said.

"But sometimes when a team lacks confidence, just to have something new to believe helps them to focus and, overall, the fact that we conceded three at West Brom, three at Crystal Palace, I felt that it was needed.

"I felt that recently we were bit vulnerable defensively. [The tactical change was] to give a bit more reassurance to the team. Recently we faced many direct games.

"It worked well in the first half, we didn't give any chances away and were quite solid. On set-pieces in the second half, maybe on one or two occasions I felt that we could have been a bit more dominant in the air."

Goals from prized possessions Alexis Sanchez and Mesut Ozil fired the visitors to an important win at the Riverside Stadium - one that puts them within seven points of fourth place.

Alvaro Negredo's 50th minute equaliser offered Boro hope of an upset but the home side were unable to find a second. Ozil's close range strike proved to be the difference following what was a another subdued performance from the German.

Sanchez celebrates his opener with Giroud (Getty)

For Wenger, the result was mentally significant. "I think in the first half it was tied because we defended very well. And after that we were tested just after half-time because it came back to 1-1.

"And then we were tested mentally and found the response to win the game, that's we needed and what we wanted.

"A bit maybe we did ride our luck on a little bit on a couple of occasions on crosses, but overall we were a bit more solid defensively today."

For Steve Agnew, defeat was a difficult pill to swallow but he expressed his pride in the side following a valiant display.

"The players were amazing," he said. "I couldn’t ask more from them."